Journal articles: 'Ferrite (Magnetic materials)'

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Sangaa, Deleg, Baatartsogt Khongorzul, Enkhnaran Uyanga, Narmandakh Jargalan, Namsrai Tsogbadrakh, and Hideyuki Hirazawa. "An Overview of Investigation for Ferrite Magnetic Nanomaterial." Solid State Phenomena 271 (January 2018): 51–63. http://dx.doi.org/10.4028/www.scientific.net/ssp.271.51.

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In recent time, interest to ferrite magnetic nanomaterials has considerably grown mainly due to their much promising medical and biological applications. The spinel ferrite powder samples having high heat generation ability in AC magnetic field was studied for application to hyperthermia treatment of cancer tumor. These properties of ferrites are strongly depending on their chemical composition, ion distribution, spin orientation and method of preparation in general and crystal structure in particular nature of the material. In this study, several samples of ferrite magnetic structures were investigated by neutron diffraction. The explanation of the mechanism to occurs the heat generation ability in the magnetic materials and the electronic and magnetic states of ferrite-spinel – type structures were theoretically defined by the first-principles calculations within the framework of DFT.

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Chandrasekar, S., and B. Bhushan. "Control of Surface Finishing Residual Stresses in Magnetic Recording Head Materials." Journal of Tribology 110, no. 1 (January 1, 1988): 87–92. http://dx.doi.org/10.1115/1.3261581.

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Surface finishing of magnetic recording head materials, such as ferrites, by diamond grinding and lapping results in a residual compressive stress on the surface. Residual stresses alter the magnetic properties of the ferrite causing the recording head performance to deteriorate. Hence, they need to be minimized. This paper considers the role of two processing techniques—annealing and chemical lapping—in controlling residual stress in ferrites. The effect of these processing techniques on various mechanical and physical properties of finished ferrites and the mechanism of residual stress control are discussed.

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Mei, Li-Then, Hsing-I. Hsiang, and Hui-Wen Ye. "A Novel Low-Temperature-Fired Multifunctional Varistor-Magnetic Ferrite Materials." Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2012, CICMT (September 1, 2012): 000641–49. http://dx.doi.org/10.4071/cicmt-2012-tha42.

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A novel low temperature-fired (950°C) multifunctional varistor-magnetic ferrite materials can be obtained by adding V2O5 into CuCr0.2Fe1.8O4 ferrites. The relationship between the grain-boundary composition and varistor properties were investigated using scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersion spectroscopy (EDS), and X-ray photoelectric spectroscopy (XPS). The addition of V2O5 can effectively reduce the sintering temperature of CuCr0.2Fe1.8O4 ferrites to temperatures of lower than 950°C. Moreover, the V5+ ions occupied the octahedral site of spinel structure and acted as donor dopant, which resulted in the semiconductive grain. The copper-rich observation at the grain boundary based on the TEM and EDS results implied that copper oxide would possibly develop at the grain boundary as the acceptor state, forming double Schottky barriers with the n-type semiconductor grains.

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Hsiang, Hsing-I., Jui-Fu Chueh, and Liang-Fang Fan. "Key Technology and Materials for the Development of DC-DC Converter Module." Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2015, CICMT (September 1, 2015): 000246–57. http://dx.doi.org/10.4071/cicmt-wp23.

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Portable devices are often powered by batteries and DC-DC converters are used to convert battery energy to supply power for microprocessors and integrated circuits. Portable electronic devices are required to be compact and, hence, space for converters is very limited. Therefore, the demand for integrating individual components into modules to reduce the size and increase the power density of DC-DC converters is increasing. It is important to develop a low temperature sintering NiCuZn ferrites with a superior DC-bias-superposition characteristic; the nonmagnetic materials co-fired with the magnetic NiCuZn ferrites, and the low-pressure assisted constrained sintering process for the large area NiCuZn ferrites substrates for the DC-DC converter modules. This study successfully developed the key technologies and materials for the development of DC-DC converter module. It integrated the magnetic NiCuZn ferrites with superior DC-bias superposition characteristic and nonmagnetic ferrite materials using multilayer ceramic processing and low-pressure assisted constrained sintering technologies to prepare a large area NiCuZn ferrite substrate for DC-DC converter module.

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Polevoy, S., G. Kharchenko, S. Tarapov, O. Kravchuk, K. Kurselis, B. Chichkov, and N. Slipchenko. "A magnetoactive metamaterial based on a structured ferrite." RADIOFIZIKA I ELEKTRONIKA 26, no. 1 (2021): 28–34. http://dx.doi.org/10.15407/rej2021.01.028.

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Subject and Purpose. The use of spatially structured ferromagnets is promising for designing materials with unique predetermined electromagnetic properties welcome to the development of magnetically controlled microwave and optical devices. The paper addresses the electromagnetic properties of structured ferrite samples of a different shape (spatial geometry) and is devoted to their research by the method of electron spin resonance (ESR). Methods and methodology. The research into magnetic properties of structured ferrite samples was performed by the ESR method. The measurements of transmission coefficient spectra were carried out inside a rectangular waveguide with an external magnetic field applied. Results. We have experimentally shown that over a range of external magnetic field strengths, the frequency of the ferromagnetic resonance (FMR) of grooved ferrite samples (groove type spatial geometry) increases with the groove depth. The FMR frequency depends also on the groove orientation relative to the long side of the sample. We have shown that as the external static magnetic field approaches the saturation field of the ferrite, the FMR frequency dependence on the external static magnetic field demonstrates "jump-like" behavior. And as the magnetic field exceeds the ferrite saturation field, the FMR frequency dependence on the groove depth gets a monotonic character and rises with the further growth of the field strength. Conclusion. We have shown that the use of structured ferrites as microwave electronics components becomes reasonable at magnetic field strengths exceeding the saturation field of the ferrite. At these fields, such a ferrite offers a monotonically increasing dependence of the resonant frequency on the external magnetic field and on the depth of grooves on the ferrite surface. Structured ferrites are promising in the microwave range as components of controlled filters, polarizers, anisotropic ferrite resonators since they can provide predetermined effective permeability and anisotropy

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Liu, Robert, and H. T. Ou. "Synthesis and Application of Magnetic Photocatalyst of Ni-Zn Ferrite/TiO2from IC Lead Frame Scraps." Journal of Nanotechnology 2015 (2015): 1–7. http://dx.doi.org/10.1155/2015/727210.

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IC lead frame scraps with about 18.01% tin, 34.33% nickel, and 47.66% iron in composition are industrial wastes of IC lead frame production. The amount of thousand tons of frame scraps in Taiwan each year is treated as scrap irons. Ni-Zn ferrites used in high frequent inductors and filters are produced from Ni-Zn ferrite powders by pressing and sintering. The amount of several ten thousand tons of ferrites ofNi1-XZnXFe2O4in compositions is consumed annually in the whole world. Therefore, these IC lead frame scraps will be used in this research as raw materials to fabricate magnetic ferrite powders and combined subsequently with titanium sulfate and urea to produce magnetic photocatalysts by coprecipitation for effective waste utilization. The prepared Ni-Zn ferrite powder and magnetic photocatalyst (Ni-Zn ferrite/TiO2) were characterized by ICP, XRF, XRD, EDX, SEM, SQUID, and BET. The photocatalytic activity of synthesized magnetic photocatalysts was tested by FBL dye wastewater degradation. TOC and ADMI measurement for degradation studies were carried out, respectively. Langmuir-Hinshelwood kinetic model of the prepared magnetic TiO2proved available for the treatments. Wastes are transformed to valuable magnetic photocatalysts in this research to solve the separation problem of wastewater and TiO2photocatalysts by magnetic field.

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Petrova, Elena G., Yana A. Shavshukova, Dzmitry A. Kotsikau, Kazimir I. Yanushkevich, Konstantin V. Laznev, and Vladimir V. Pankov. "Thermolysis of sprayed suspensions for obtaining highly spinel ferrite nanoparticles." Journal of the Belarusian State University. Chemistry, no. 1 (February 21, 2019): 14–21. http://dx.doi.org/10.33581/2520-257x-2019-1-14-21.

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Thermal treatment of ferrite magnetic nanoparticles in NaCl matrix gives an opportunity to increase their specific magnetization with preservation of nanoscale size. Composite materials based on mixed ferrites Co0.65Zn0.35Fe2O4 and Mg 0.5Zn0.5Fe2O4 were synthesized by spray-drying of aqueous suspensions in presence of NaCl and annealed at 300 –900 °C. The microstructure and phase composition of nanoparticles before and after annealing were studied by scanning and transmission electron microscopy (SEM and TEM), X-ray diffraction analysis and IR spectroscopy. The magnetic properties of nanoparticles were estimated using a ponderomotive method of measuring the specific magneti zation at room temperature in a magnetic field with an induction of 0.86 T. The increase of the annealing temperature up to 900 °C was established to lead to the increase in the specific magnetization of ferrites – from 32.79 to 91.3 emu/g (Co0.65Zn0.35Fe2O4) and from 2.76 to 22.31 emu/g (Mg 0.5 Zn 0.5Fe2O4) due to recrystallization processes and increase of crystallinity degree of the ferrites. Due to the NaCl insulating layer, the particle size increases just slightly (from ~ 10 nm before annealing to ~ 60 nm after annealing at 900 °C). This method is effective for substantial increase in specific magnetization of ferrite nanoparticles with preservation of their nanoscale size.

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Yang, Shi Qing, Pi Feng Yu, Tao Hua Liang, Qing Xue Yang, and Yi Feng Meng. "The Influence of Doping Both NiO and CoO on the Properties of Low-Loss and High Bs MnZn Ferrites." Advanced Materials Research 1096 (April 2015): 309–14. http://dx.doi.org/10.4028/www.scientific.net/amr.1096.309.

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MnZn soft ferrite materials with NiO-CoO dopant are prepared by conventional oxide technique.The influences of CoO and NiO addition on the microstructure and magnetic properties of low-loss and high Bs MnZn ferrites are investigated. The present results show that MnZn soft ferrite materials with CoO addition of 0.1wt% and NiO addition of 1.28wt% possess both homogeneous grains and high saturation magnetic flux density. The lowest loss point is located at 100°C. The valley point of power loss shifts to higher temperature with increasing of NiO dopant. The power losses decrease and sintering density increases with increase of CoO addition. The sintered MnZn ferrite materials based upon a specific sinter curve possesss excellent comprehensive properties: μi=2198 , Pcv=319 kw/m3 , Bs=540mT (T=25°C), Bs=451mT (T=100°C).

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PENCHAL REDDY, M., M. VENKATA RAMANA, N. RAMA MANOHAR REDDY, K. V. SIVA KUMAR, R. RAMA KRISHNA REDDY, W. MADHURI, K. SIVA KUMAR REDDY, P. SREEDHARA REDDY, and V. R. K. MURTHY. "STRUCTURAL, ELECTRICAL AND MAGNETIC CHARACTERIZATION OF Ni–Cu–Zn SPINEL FERRITES." Modern Physics Letters B 25, no. 03 (January 30, 2011): 211–22. http://dx.doi.org/10.1142/s0217984911025626.

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Ni – Cu – Zn ferrite materials have been extensively used in multilayer chip inductors because of their remarkable properties at higher frequencies. In the present work, single phase Ni 0.35 Cu 0.05 Zn 0.60 Fe 1.98 O 4-δ ferrite, has been prepared by microwave sintered (MS) method. In comparison with the conventional sintering method (CS), the sintering temperature and time for this MS method were significantly reduced to 30 min and 950°C from 5 h and 1250°C for the CS process. The frequency dependence of the dielectric properties such as dielectric constant (ε'), dielectric loss ( tan δ) were studied. The temperature dependence of magnetic initial permeability (μi) was studied. The saturation magnetization was also studied as a function of magnetic field. These microwave sintered ferrites results were compared with the properties of ferrites prepared by conventional sintering method in normal heating. Microwave sintering improves structural as well as electromagnetic parameters measured and thus makes the ferrite more suitable in microwave applications and electromagnetic devices.

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Soloman, M. A., Philip Kurian, and M. R. Anantharaman. "Dielectric and Mechanical Properties of Rubber Ferrite Composites Containing Barium Ferrite." Progress in Rubber, Plastics and Recycling Technology 18, no. 4 (November 2002): 269–82. http://dx.doi.org/10.1177/147776060201800404.

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The incorporation of various types of ferrites in rubber matrixes leads to the development of rubber ferrite composites (RFC). These RFC have a large number of applications as flexible magnets, high-tech sensors, for telecommunication and radiowave absorbers. Both natural and synthetic rubber has the potential of being value added by the incorporation of ferrites. Applications like microwave absorbers warrant that these composites have an appropriate dielectric strength with the required magnetic property. This can be achieved by synthesizing composites based on natural rubber and ferrites. In this paper we report the synthesis of RFC containing barium ferrite according to a specific recipe and its evaluation of dielectric and mechanical properties.

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Escamilla-Pérez, A. M., D. A. Cortés-Hernández, J. M. Almanza-Robles, D. Mantovani, and P. Chevallier. "Magnetic Properties of Mg_0.4Ca_0.6Fe₂O₄ Nanoparticles Synthesized by Sol-Gel Method for Hyperthermia Treatment." Key Engineering Materials 631 (November 2014): 193–97. http://dx.doi.org/10.4028/www.scientific.net/kem.631.193.

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Powders of Mg0.4Ca0.6Fe2O4were prepared by sol-gel using ethylene glycol and Mg, Ca and Fe nitrates as starting materials. Those powders were heat treated at different temperatures (300, 400, 500 and 600 °C) for 30 min. The materials obtained were characterized by X-ray diffraction (XRD) and vibrating sample magnetometry (VSM). The Ca-Mg ferrite with the most appropriate magnetic properties was further analyzed by transmission electron microscopy (TEM). The heating capability of the nanoferrites was also tested via magnetic induction. The XRD patterns of these Ca-Mg ferrites showed a cubic inverse spinel structure. Furthermore, neither traces of hematite nor orthorhombic Ca ferrite phases were detected. Moreover, all the Ca-Mg ferrites are superparamagnetic and the particle size distribution of these Ca-Mg magnetic nanoparticles exhibits an average diameter within the range of 10-14 nm. The needed temperature for hyperthermia treatment was achieved at around 12 min.

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Miclea, Cornel, Constantin Tanasoiu, Corneliu Florin Miclea, I. Spanulescu, M. Cioangher, and C. T. Miclea. "Magnetic Temperature Transducers Made from Copper Based Soft Ferrite." Advances in Science and Technology 54 (September 2008): 62–69. http://dx.doi.org/10.4028/www.scientific.net/ast.54.62.

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Soft ferrites in the CuZnTi system, having the chemical composition Cu1-x-yZnxTiyFe2O4 with 0.5£x£0.7 and 0.00£y£0.05 were investigated as a function of composition, sintering temperature and cooling speed, in order to obtain materials with different Curie temperatures, between 30 and 180 oC and very high change rate of permeability with temperature around their Curie points. Such materials are well suited to use as high sensitive magnetic temperature sensors and transducers for temperature control. Zn and Ti additions to copper ferrite change the Curie temperature in a controllable manner, thus being possible to produce ferrite material with a fine control of the Curie point at any desired temperature. Most important was the behavior of magnetic permeability with temperature around the Curie point, where it may change with about 60 %/oC by a proper choice of the cooling speed of samples from the sintering temperature to room temperature. This makes such materials extremely attractive as magnetic temperature sensors of high sensitivity. Two applications of such materials as temperature sensors, namely an ultrathermostat and an on-off switch type relay were designed. Their functionality and performances are presented and discussed.

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Chanadee, T. "Combustion synthesis of nickel-ferrite magnetic materials." International Journal of Self-Propagating High-Temperature Synthesis 26, no. 1 (January 2017): 40–43. http://dx.doi.org/10.3103/s1061386217010058.

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Musat, V., O. Potecasu, R. Belea, and P. Alexandru. "Magnetic materials from co-precipitated ferrite nanoparticles." Materials Science and Engineering: B 167, no. 2 (March 2010): 85–90. http://dx.doi.org/10.1016/j.mseb.2010.01.038.

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Ušáková, Mariana, Elemír Ušák, Martin Šoka, and Ján Lokaj. "The influence of selected ions on various characteristics of Nickel-Zinc ferrites." Journal of Electrical Engineering 69, no. 6 (December 1, 2018): 449–53. http://dx.doi.org/10.2478/jee-2018-0072.

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Abstract One of acknowledged methods remarkably improving structural, magnetic and electrical properties of spinel ferrite systems is the substitution of iron ions by some trivalent ions. In the family of spinel ferrites, thanks to its high saturation magnetization and electrical resistivity as well as low losses, the nickel-zinc ferrite is a very important magnetic material used in many applications in electrical engineering and electronics. The properties of these materials are in general dependent upon chemical composition, method of preparation, stoichiometry, sintering time, temperature as well as the atmosphere, etc. In this study the influence of appropriately selected ions (M = In3+, Nd3+, Dy3+ and Er3+), partly replacing Fe3+, on the microstructure and magnetic properties of spinel ferrite with the composition Ni0.42Zn0.58M0.02Fe1.98O4 fabricated by means of standard ceramic technology was investigated.

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Huang, Kai, Xiansong Liu, Shuangjiu Feng, Jiangying Yu, Xiaofei Niu, Farui Lv, and Xing Huang. "Structural and Magnetic Properties of Cr-Substituted NiCuZn Ferrite." High Temperature Materials and Processes 35, no. 5 (May 1, 2016): 531–34. http://dx.doi.org/10.1515/htmp-2014-0223.

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AbstractCr-substituted Ni0.2Cu0.2Zn0.6Fe2–xCrxO4 ferrites (where x = 0–1.0) were prepared by solid-state reaction. The effects of Cr content on structural and magnetic properties were investigated. X-ray diffraction (XRD) revealed the formation of ferrite particles with cubic spinel structure. The lattice parameter and average crystallite sizes are much dependent on the chromium content and are found to decrease with its increasing. The initial permeability (μi) and saturation flux density (Bs) decrease with the increasing Cr content. In addition, without substituted ceramic samples possess lower quality factor (Q factor) than the NiCuZn ferrites with Cr substituted.

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Liu, Wen Bao, Bing Jun Yang, Wan Li Yang, Wen Li, Jiao Yang, and Mei Zhen Gao. "Synthesis of Magnetic Particles and Silica Coated Core-Shell Materials." Advanced Materials Research 631-632 (January 2013): 490–93. http://dx.doi.org/10.4028/www.scientific.net/amr.631-632.490.

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Ferrite particles were prepared by hydrothermal process at high temperature. The characterization of ferrite was examined by XRD, Mössbauer spectrum, and SEM. The XRD and Mössbauer spectrum confirmed that ferrite particles have a Fe3O4 inverse spinel structure, the SEM results show that each Fe3O4 particles were composed of many smaller magnetite nanoparticles. The as-synthesized Fe3O4 particles were modified by sodium citrate then further coated with SiO2 layer through the modified stöber method. The composited Fe3O4@SiO2 microspheres exhibited outstanding monodispersity and magnetic property.

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Mirshekari, Gholam Reza, Shiva Sadat Daee, Hossein Mohseni, Sima Torkian, Mehri Ghasemi, Moosa Ameriannejad, Molood Hoseinizade, et al. "Structure and Magnetic Properties of Mn-Zn Ferrite Synthesized by Glycine-Nitrate Auto-Combustion Process." Advanced Materials Research 409 (November 2011): 520–25. http://dx.doi.org/10.4028/www.scientific.net/amr.409.520.

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Manganese-Zinc ferrites belong to the group of soft ferrite materials characterized by high magnetic permeability and low power loses. These materials are mainly used as cores for inductors, transformers, recording heads and noise filters among others. In this study, nanocrystalline Mn-Zn ferrite with the chemical formula Mn1-xZnxFe2O4withx=0.2, 0.4, 0.6, 0.8 has been successfully synthesized by glycine-nitrate auto-combustion process using glycine as a fuel and nitrates as oxidants. The structures and magnetic properties of the resulting powder were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM). It is revealed from the XRD pattern than a significant amount nanocrystalline Mn1-xZnxFe2O4ferrite with average crystallite size in the range 43.25-66.7 nm has been formed. The magnetic measurement gives a typical value of saturation magnetic of 34-69 emu/g and coercivity of 40-60 Oe.

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Gupta, Meenal, Anusree Das, Dipankar Das, Satyabrata Mohapatra, and Anindya Datta. "Chemical Synthesis of Rare Earth (La, Gd) Doped Cobalt Ferrite and a Comparative Analysis of Their Magnetic Properties." Journal of Nanoscience and Nanotechnology 20, no. 8 (August 1, 2020): 5239–45. http://dx.doi.org/10.1166/jnn.2020.18528.

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Lanthanum (La) and gadolinium (Gd) doped cobalt ferrite nanoparticles are synthesized using a soft chemical approach. The analysis of these ferrites using X-ray diffraction (XRD) and transmission electron microscopy (TEM) shows that lattice spacing decreases in the doped ferrite samples. Magnetization data indicates towards the decrease of saturation magnetisation but increase in coercivity with doping. Mössbauer spectroscopy measurements at room temperature indicate increased occupancy of trivalent cations at tetrahedral site. The addition of rare earth dopants reduces the hard-magnetic character of cobalt ferrite.

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Vereda, Fernando, Juan de Vicente, and Roque Hidalgo-Álvarez. "Synthesis of Ni ferrite and Co ferrite rodlike particles by superposition of a constant magnetic field." Journal of Materials Research 23, no. 6 (June 2008): 1764–75. http://dx.doi.org/10.1557/jmr.2008.0218.

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We report the fabrication of micron-sized rodlike particles of nonstoichiometric Co and Ni ferrites by aging coprecipitated Fe(OH)2 and M(OH)2—where M is either Ni or Co—at 90 °C in the presence of an external magnetic field (B ≈ 405 mT). Potassium nitrate was used as a mild oxidant. Resultant particles were analyzed by means of electron microscopy, x-ray powder diffraction (XRD), magnetometry, energy dispersive x-ray (EDX) spectrometry, and atomic absorption spectroscopy. Rodlike particles of both types of ferrite exhibited a relatively uniform thickness, an average aspect ratio close to 10, and have a spinel crystalline structure. EDX spectrometry and atomic absorption spectroscopy confirmed the incorporation of Ni2+ and Co2+ in the respective ferrite particles. The incorporation of Co2+ led to non-negligible remanence and coercivity. The incorporation of Ni2+ led to a lower saturation magnetization, whereas the remanence and coercivity of the Ni ferrite were very low, still typical of a soft ferrimagnetic material. The mechanism of formation of the rodlike particles was investigated by the time-dependent observation of growing Ni ferrite rods.

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Fernandes, Ricardo J. C., Carlos A. B. Magalhães, Ana Rita O. Rodrigues, Bernardo G. Almeida, Ana Pires, André Miguel Pereira, João Pedro Araujo, Elisabete M. S. Castanheira, and Paulo J. G. Coutinho. "Photodeposition of Silver on Zinc/Calcium Ferrite Nanoparticles: A Contribution to Efficient Effluent Remediation and Catalyst Reutilization." Nanomaterials 11, no. 4 (March 24, 2021): 831. http://dx.doi.org/10.3390/nano11040831.

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The efficient photodegradation of textile dyes is still a challenge, especially considering resistant azo dyes. In this work, zinc/calcium mixed ferrite nanoparticles prepared by the sol–gel method were coupled with silver by a photodeposition method to enhance the photocatalytic potency. The obtained zinc/calcium ferrites are mainly cubic-shaped nanoparticles sized 15 ± 2 nm determined from TEM and XRD and an optical bandgap of 1.6 eV. Magnetic measurements indicate a superparamagnetic behavior with saturation magnetizations of 44.22 emu/g and 27.97 emu/g, respectively, for Zn/Ca ferrite and Zn/Ca ferrite with photodeposited silver. The zinc/calcium ferrite nanoparticles with photodeposited silver showed efficient photodegradation of the textile azo dyes C.I. Reactive Blue 250 and C.I. Reactive Yellow 145. Subsequent cycles of the use of the photocatalyst indicate the possibility of magnetic recovery and reutilization without a significant loss of efficiency.

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Jacobo, Silvia E., and P. G. Bercoff. "Coercivity Enhancement of Hexagonal Ferrites." Solid State Phenomena 202 (May 2013): 113–25. http://dx.doi.org/10.4028/www.scientific.net/ssp.202.113.

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Hexagonal ferrites have been widely used as permanent magnets since their discovery in the 1950s. In spite of their relatively modest magnetic properties, ferrite magnets still show the best performance-to-cost ratio and different investigators are trying to improve their magnetic capabilities by using different synthesis methods and compositions. Different scientific investigations and techniques (Mössbauer spectrometry, X-ray diffraction, and magnetic measurements) have allowed to optimize the permanent magnet properties of rare earth substituted hexagonal ferrite magnets such as La-Co and Nd-Co Sr and Ba ferrites. However, the solubility of rare earth ions in M-type hexaferrite is very low and their introduction leads to the formation of secondary phases, which must be avoided in order to obtain permanent magnets with optimal properties. We report results on enhanced coercivity of hexagonal Sr ferrites with Nd-Co substitution synthesized by the self-combustion method and calcination at 1100°C for two hours. The synthesis of this kind of ferrite is performed with a deficient, non-stoichiometric iron content (ratio Fe/ Sr1xRxof 10 and 11 instead of 12) in order to explore the presence of secondary phases. Comparison with samples of the same composition and stoichiometric formulation is made. Samples with lower iron content show the highest saturation magnetization, remanence and/or coercivity, indicating that the best results for applications of this ferrite will be obtained with an iron deficiency in the stoichiometric formulation. Nd substitution enhances the ferrite anisotropy and coercivity with respect to the unsubstituted sample.

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Vallet-Regí, M., S. Nicolopoulos, and J. M. González-Calbet. "HREM study of M, Y and W hexagonal type ferrites." Proceedings, annual meeting, Electron Microscopy Society of America 48, no. 4 (August 1990): 776–77. http://dx.doi.org/10.1017/s0424820100177015.

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Hexagonal ferrites have similar structural symmetries and are built by the same structural units. HREM has proved to be an excellent tool to identify individual stacking bloks, in M, Y and W hexaferrites.M, Y and W hexagonal type ferrites are well-known magnetic materials for applications. Some previous electron microscopy studies on these ferrites, reveal a variety of new phases coming from the microsyntactic intergrowth of M, Y and W structures. We report in this paper some microstructural features of these ferrites.BaFe12O19 (M) hexagonal ferrite was synthetized by using the standard ceramic technique. Crystals of Y type ferrite (nominal composition: BaLi0.5Fe0.5ZnFe16027) were prepared from stoichiometric amounts of BaCO3, ZnO and LiCO3. The synthesis of W-type ferrite (formula: Ba2Zn2Fe16027) is described elsewhere.Samples for observation were prepared by grinding powders of the above ferrites under acetone. HREM study was performed at the "Centro de Microscopía Electrónica, Univ. Complutense" using both 400 Kv and 200 Kv electron microscopes (JEM-400EX and JEM-200FX)

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Akbar Notonegoro, Hamdan, Bambang Soegijono, and Isom Mudzakir. "Engineering of magnetic properties in doped bismuth ferrite materials." MATEC Web of Conferences 218 (2018): 04027. http://dx.doi.org/10.1051/matecconf/201821804027.

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The engineering of magnetic behaviour of Li/Zn doped BiFeO3 had been done by synthesized a polycrystalline of BiFeO3, Bi0.96Li0.02FeO3, and Bi0.95Zn0.05FeO3. Investigation of crystallite structure and magnetic properties of the sampel had been done by X-ray diffraction and VSM analysis. At room temperature, the lithium and zinc doped bismuth ferrite has conducted a different magnetic behaviour. Within the ferromagnetic region, an increases of magnetic saturation or enlarger magnetic coercivity were identified. Doping lithium resulted in increasing magnetic saturation (Ms) and magnetic remanent (Mr), significantly. Meanwhile, doping zinc resulted in enlarger of magnetic coercivity coincide with the reveal of Bi20FeO40 as the second phase.

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Kostishin, V. G., R. M. Vergazov, S. B. Menshova, I. M. Isaev, and A. V. Timofeev. "The effect of alloying additives on the magnetic permeability and permittivity of ferrite spinel." Industrial laboratory. Diagnostics of materials 87, no. 1 (January 19, 2021): 30–34. http://dx.doi.org/10.26896/1028-6861-2021-87-1-30-34.

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Coatings made of the materials that effectively absorb radiation, e.g., ferrite materials, are used to reduce the level of electromagnetic radiation in rooms containing household or industrial equipment. It is known that significant dissipation of the radiation energy is provided by the thickness of the shielding coating which should be comparable to the length of the electromagnetic wave in the material which, in turn, significantly decreases at high values of the magnetic permeability and permittivity of the radio-absorbing material. Ferrite radio-absorbing coatings are characterized by the high heat resistance, low flammability and small (10 – 20 mm) thickness. However, at frequencies less than 40 MHz, plates with a thickness of more than 30 mm are to be used to provide the effective absorption, and the weight and cost of the coatings increase significantly. The results of studying the effect of the sintering temperature and micro-additives of titanium, calcium and bismuth oxides on the dielectric constant of Ni- and Mn-Zn radio-absorbing ferrites are presented. Reactively pure starting oxide components with a basic substance content of more than 99.6 % wt. were used to synthesize samples using traditional oxide technology. It is shown that alloying with bismuth and titanium oxides is rather effective for obtaining radio-absorbing ferrites with a combination of high values of the magnetic permeability and dielectric permittivity. The obtained results can be used in production of ferrite radio- absorbing materials operating in the megahertz range.

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JIAO, QIGANG, YI ZHANG, YA ZHAI, XIAOJUN BAI, WEI ZHANG, JUN DU, and HONGRU ZHAI. "MAGNETIC PROPERTIES AND INDUCTION HEATING OF NiZn FERRITE NANOPARTICLES." Modern Physics Letters B 22, no. 15 (June 20, 2008): 1497–505. http://dx.doi.org/10.1142/s0217984908016212.

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A series of nanoparticle powders of Ni x Zn 1-x Fe 2 O 4 (x = 0, 0.30, 0.40, 0.50, 0.55, 0.60, 0.70 and 1.0) ferrites was synthesized by the refluxing method at relatively low temperatures. The average size of nanoparticles is about 20 nm. The magnetic properties and induction heating behavior were investigated. On increasing the Ni content, x, from 0 to 0.50, the saturation magnetization and permeability increased, and then decreased with further increasing Ni content with the bulk Ni – Zn ferrite. The maximum value of magnetization was about 50 emu/g near x = 0.50, where the induction heating rate and induction heating final temperature of the ferrite-water suspension also showed maximum values. The specific absorption rate obtained from the initial induction heating rate curve was found to be linearly proportional to the square of the alternating magnetic field, which is roughly consistent with the theoretical power loss of magnetic materials in the alternating field.

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Fernandes, Ricardo J. C., Carlos A. B. Magalhães, Carlos O. Amorim, Vítor S. Amaral, Bernardo G. Almeida, Elisabete M. S. Castanheira, and Paulo J. G. Coutinho. "Magnetic Nanoparticles of Zinc/Calcium Ferrite Decorated with Silver for Photodegradation of Dyes." Materials 12, no. 21 (October 31, 2019): 3582. http://dx.doi.org/10.3390/ma12213582.

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Magnetic nanoparticles of zinc/calcium ferrite and decorated with silver were prepared by coprecipitation method. The obtained nanoparticles were characterized by UV/Visible absorption, XRD, TEM and SQUID. The mixed zinc/calcium ferrites exhibit an optical band gap of 1.78 eV. HR-TEM imaging showed rectangular nanoplate shapes with sizes of 10 ± 3 nm and aspect ratio mainly between 1 and 1.5. Magnetic measurements indicated a superparamagnetic behavior. XRD diffractograms allowed a size estimation of 4 nm, which was associated with the nanoplate thickness. The silver-decorated zinc/calcium ferrite nanoparticles were successfully employed in the photodegradation of a model dye (Rhodamine B) and industrial textile dyes (CI Reactive Red 195, CI Reactive Blue 250 and CI Reactive Yellow 145). The nanosystems developed exhibited promising results for industrial application in effluent photoremediation using visible light, with the possibility of magnetic recovery.

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28

Matz, Richard, Dieter Götsch, Thomas Goßner, Roman Karmazin, Ruth Männer, and Bernhard Siessegger. "Power Inductors in Ceramic Multilayer Circuit Boards." Journal of Microelectronics and Electronic Packaging 5, no. 4 (October 1, 2008): 161–68. http://dx.doi.org/10.4071/1551-4897-5.4.161.

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Power electronic inductors, with values of several μH, have been integrated into thermally stable ceramic multilayer circuit boards by the use of NiZnCu and MnZn ferrite tapes in low temperature cofired ceramic (LTCC) technology. These ferrites are particularly attractive for switched mode power supplies in automation, drives, and consumer applications, where the miniaturization of modules is triggered by advances in transistor technology and switching frequencies. The small signal analysis of embedded individual inductors and coupled transformer coils reveals the generic design rules for these components and additional materials properties beyond those accessible by ring core measurements. In the process of adapting the materials to LTCC, the distinct differences between the two materials become blurred, for example, they can be engineered to exhibit similar cutoff frequencies. NiZnCu ferrite, which is sinterable in air, may even achieve higher permeability than MnZn ferrite. The latter, however, shows higher saturation flux density and current capacity of buried inductors for power line filters. The coupled inductor design in a transformer is particularly ruled by the shunt capacitance inside the coils and by the fact that Maxwell equations preclude strong magnetic coupling between ferrite-embedded conductor lines. While parasitic capacitances remain tolerable for standard dielectric layer material up to several MHz, the need for magnetic coupling requires a fabrication process for magnetic vias.

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Owolabi, Taoreed O., Tawfik A. Saleh, Olubosede Olusayo, Miloud Souiyah, and Oluwatoba Emmanuel Oyeneyin. "Modeling the Specific Surface Area of Doped Spinel Ferrite Nanomaterials Using Hybrid Intelligent Computational Method." Journal of Nanomaterials 2021 (August 18, 2021): 1–13. http://dx.doi.org/10.1155/2021/9677423.

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Spinel ferrites nanomaterials are magnetic semiconductors with excellent chemical, magnetic, electrical, and optical properties which have rendered the materials useful in many technological driven applications such as solar hydrogen production, data storage, magnetic sensing, converters, inductors, spintronics, and catalysts. The surface area of these nanomaterials contributes significantly to their targeted applications as well as the observed physical and chemical features. Experimental doping has shown a great potential in enhancing and tuning the specific surface area of spinel ferrite nanomaterials while the attributed experimental challenges call for viable theoretical model that can estimate the surface area of doped spinel ferrite nanomaterials with high degree of precision. This work develops stepwise regression (STWR) and hybrid genetic algorithm-based support vector regression (GBSVR) intelligent model for estimating specific surface area of doped spinel ferrite nanomaterials using lattice parameter and the size of nanoparticle as descriptors to the models. The developed hybrid GBSVR model performs better than STWR model with the performance improvement of 7.51% and 22.68%, respectively, using correlation coefficient and root mean square error as performance metrics when validated with experimentally measured specific surface area of doped spinel ferrite nanomaterials. The developed GBSVR model investigates the influence of nickel, yttrium, and lanthanum nanoparticles on the specific surface area of different classes of spinel ferrite nanomaterials, and the obtained results agree excellently well with the measured values. The accuracy and precision characterizing the developed model would be of immense importance in enhancing specific surface area of doped spinel ferrite nanomaterial prediction with circumvention of experimental stress coupled with reduced cost.

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30

Bhalla, Deepak, S. K. Aggarwal, G. P. Govil, and Ish Kakkar. "Manufacturing of Manganese-Zinc Soft Ferrite by Powder Metallurgy." Open Materials Science Journal 4, no. 1 (February 3, 2010): 26–31. http://dx.doi.org/10.2174/1874088x010040100026.

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Objective of this paper is, improvement of quality of Mn-Zn soft ferrites manufactured by powder metallurgy and overall output yield of it's plant. The efforts have been made to synthesize the crucial parameters which are responsible for better material preparation, pressing and sintering. By adopting these recommendations, the rejection rate is substantially reduced and the variation in magnetic properties is less. Data, which give more uniformity in bigger lots and are responsible for more uniform magnetic properties, have been discussed. Simple, quality-control instruments and their measurement methods which can be incorporated for stage inspection have been explained. The additives for better ferrite powder preparation, granules making and to obtain better magnetic have been discussed. Improved pressing, sintering, porosity, density and permeability relationship have been drawn. A sintering method to obtain better sintered density and high permeability in ferrites is also explained.

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31

Glitzky, Carsten, Torsten Rabe, Markus Eberstein, Wolfgang A. Schiller, Jörg Töpfer, Stefan Barth, and Annette Kipka. "LTCC-Modules with Integrated Ferrite Layers—Strategies for Material Development and Co-Sintering." Journal of Microelectronics and Electronic Packaging 6, no. 1 (January 1, 2009): 49–53. http://dx.doi.org/10.4071/1551-4897-6.1.49.

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The integration of passive components (resistors, capacitors, inductors) into LTCC modules is a challenging task in multilayer ceramics technology. We report on multilayer assemblies consisting of combined layers of ferrite and dielectric LTCC tapes. Ni-Cu-Zn ferrites with maximum shrinkage at 900°C were processed to green tapes and laminated with dielectric LTCC tapes. Cosintering at 900°C led to multilayers with different defects such as incomplete densification of the ferrite layers, cracks, and warpage. Since ferrite tapes do not really allow compositional changes without deterioration of magnetic properties, the dielectric tape was modified with the following objectives: (i) matching of the shrinkage curves of dielectric and ferrite materials, (ii) adjusting the coefficients of thermal expansion to avoid cracking during cooling, and (iii) controlling of interface reactions. Using this concept we fabricated dense and defect-free multilayers consisting of dielectric and ferrite layers. However, compositional changes of the individual ferrite tapes require the development of a specific dielectric tape material with tailored properties.

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32

Bierlich, S., J. T[ouml]pfer, S. Barth, B. Pawlowski, J. M[uuml]ller, and H. Bartsch-Torres. "Cofiring behavior of multilayer inductors based on substituted Y- and M-type hexagonal ferrites." Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2012, CICMT (September 1, 2012): 000659–63. http://dx.doi.org/10.4071/cicmt-2012-tha45.

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Sinter-active soft ferrites with adequate permeability profiles are required for the fabrication of multilayer ferrite inductors (MLFI). For MLFI fabrication, a Low Temperature Ceramic Co-firing (LTCC) process is used. Substituted hexagonal ferrites of Y-, and M-type represent an important family of soft ferrites which might operate at high-frequency conditions up to 2 GHz. However, for Ag-based multilayer inductor applications a sinter process at 900°C is required. Low-temperature sinter-ability is provided by the use of sub-micron powders and/or sintering additives. Substituted Y-type hexagonal ferrites Ba2Co2-x-yZnxCuyFe12O22 were obtained after sintering at 1000°C. Substitution of Cu for Co improved the low-temperature sintering behavior. The addition of 5wt.% Bi2O3 guarantees almost complete densification at 900°C. The saturation magnetization and permeability are significantly affected by the Zn-concentration. A maximum permeability of μ′ = 10 and cut-off frequency fg~2GHz was observed for a ferrite with y = 0.4. Co/Ti-substituted M-type BaFe12-2yCoyTiyO19 ferrites can also be used for multilayer inductors. The magneto-crystalline anisotropy changes from uniaxial to planar upon Co/Ti-substitution, and ferrites with y≥1.1 exhibit soft magnetic behavior. Ferrite powders were prepared at 1000°C. The addition of a sintering aid shifts the temperature of maximum shrinkage down to below 900°C and dense samples were obtained after firing at 900°C. A permeability of μ′ = 16 and a resonance frequency of 1 GHz was observed. Substituted M-type ferrites are stable during co-firing at 900°C and show no sign of decomposition, i.e. these materials are LTCC-compatible. Ferrite tapes were prepared by tape casting and multilayer structures were fabricated by screen printing, stacking, lamination and final co-firing. Firing was performed at LTCC conditions i.e. 900°C. We report on the co-firing behavior, microstructure and permeability of monolithic laminates. It is shown, that hexagonal Co2/Zn2Y- and Co/Ti-M-type ferrites are excellent magnetic materials for multilayer inductors.

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Kruželák, Ján, Sybill Ilisch, Ivan Hudec, and Rastislav Dosoudil. "Evaluation of Fillers Dispersion Degree in Elastomeric Magnetic Composites." Smart Materials Research 2012 (June 28, 2012): 1–8. http://dx.doi.org/10.1155/2012/532170.

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Elastomeric magnetic composites were prepared by incorporation of strontium ferrite into polymer matrices based on natural as well as butadiene rubber. Besides the rubber and ferrite, or the combinations of ferrite and carbon black (in case of natural rubber), the model rubber compounds contained only ingredients which support curing process. The study was dedicated to the observation of fillers dispersion degree in the rubber matrices and investigation of physical-mechanical and magnetic properties of prepared composites. The results indicate that the dispersion degree of ferrite in the rubber matrices is not very high, but it can be positively influenced by the addition of carbon black. Despite of the fact that ferrite exhibits only low reinforcing effect on cross-linked elastomeric materials, physical-mechanical properties can be also positively influenced by the mutual change in combinations of both fillers (ferrite and carbon black). The prepared materials seem to have suitable magnetic and elastic properties.

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Stary, O. "FORMATION OF MAGNETIC PROPERTIES OF FERRITES DURING RADIATION-THERMAL SINTERING." Eurasian Physical Technical Journal 17, no. 2 (December 24, 2020): 6–10. http://dx.doi.org/10.31489/2020no2/6-10.

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The results of a comparative analysis of the laws governing the formation of ferrite hysteresis loop parameters sintered in thermal and radiation-thermal conditions were shown. The influence of radiation exposure on the interconversion of microstructure defects and their content in ferrites, depending on the duration and temperature of treatment, was established. Also, it was shown that recrystallization grain growth under irradiation conditions is ahead of grain growth during thermal heating. The observed radiation effects were associated with the effect of radiation on the microstructure. The magnetic parameters are uniquely determined by the compaction of the sample.

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Che, Ru Xin, Chun Xia Wang, and Bing Yu. "Preparation and Magnetic Properties of the Core-Nanoshell Composite Materials Doped with Nd." Advanced Materials Research 284-286 (July 2011): 1956–60. http://dx.doi.org/10.4028/www.scientific.net/amr.284-286.1956.

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The core-nanoshell composite materials doped with Nd were prepared by a solid-state reaction method. The core is magnetic fly-ash hollow cenosphere, and the shell is the nanosized ferrite doped with Nd. The thermal decomposition process of the sample was investigated by TG- DTA. The morphology and composition of the composite materials were investigated by the X-ray diffraction analysis ( XRD ), scanning electron microscope ( SEM ) and energy disperse spectroscopy ( EDS ). The results of vibrating sample magnetometer ( VSM ) analysis indicated that the exchange-coupling interaction happens between ferrite of magnetic fly-ash hollow cenosphere and nanosized ferrite coating. The exchange-coupling interaction enhances magnetic loss of composite materials. The results show that doped with Nd can enhance the coercivity too, so the magnetic properties could be promoted further. The magnetic properties of the core-nanoshell composite material are better than that of single-phase.

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36

Ahad, Nor Azwin, Sahrim Haji Ahmad, and Jalilah Abd Jalil. "Magnetic and Electrical Properties of TPU/NR Blends Filled NiZn Ferrite." Applied Mechanics and Materials 754-755 (April 2015): 256–60. http://dx.doi.org/10.4028/www.scientific.net/amm.754-755.256.

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Blending method of two or more polymer is well-established strategy to modify the physical properties without synthesizes the new polymer system. While adding magnetic filler will change the magnetic properties of the polymer as an insulator to the materials that are magnetic. The TPU/NR blends as matrix was prepared from thermoplastic polyurethane (TPU) and natural rubber (NR) in the ratio 85/15 with 1-5 wt% NiZn ferrites. The value of saturation magnetization (Ms), remanance (Mr) increased, while coercive force (Hc) decreases with increasing filler loading. For the electrical properties, resistivity decreased and conductivity increased with the increase of NiZn ferrite loading in the blends.

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37

Bobić, J. D., G. Ferreira Teixeira, R. Grigalaitis, S. Gyergyek, M. M. Vijatović Petrović, M. Ap Zaghete, and B. D. Stojanovic. "PZT–NZF/CF ferrite flexible thick films: Structural, dielectric, ferroelectric, and magnetic characterization." Journal of Advanced Ceramics 8, no. 4 (December 2019): 545–54. http://dx.doi.org/10.1007/s40145-019-0337-1.

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AbstractThe preparation and properties of thick flexible three-phase composite films based on lead zirconium titanate (PZT) and various ferrites (nickel zinc ferrite (NZF) and cobalt ferrite (CF)) were reported in this study. Properties of three-phase composite films were compared with pure polyvinylidene fluoride (PVDF) and PZT–PVDF films. X-ray diffraction data indicated the formation of well crystallized structure of PZT and NZF/CF phases, without the presence of undesirable phases. Scanning electron micrographs showed that the ceramic particles were dispersed homogeneously in the PVDF matrix and atomic force microscopy confirmed that the size of the particles is around 30 nm. Non-saturated hysteresis loops were evident in all samples due to the presence of highly conductive ferrite phases. Under magnetic field of 10 kOe, composite films exhibited a typical ferromagnetic response. Dielectric properties were investigated in the temperature range from −128 to 250 °C and frequency range of 400 Hz–1 MHz. The results showed that the value of dielectric constant of the PVDF/PZT/ferrite composites increased about 25% above the one obtained for pure PVDF.

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38

Dmitry N. Samchenko, Gennadii М. Kochetov, and Aleksey Vasiliev. "Еnergy-saving technology for processing of galvanic sludge with obtaining of radio-absorbing materials." Environmental safety and natural resources 35, no. 3 (September 17, 2020): 30–43. http://dx.doi.org/10.32347/2411-4049.2020.3.30-43.

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The prospective for increasing of environmental safety level of industrial enterprises is considered as result of realization of energy- and resource saving technology for processing galvanic sludge by hydrophase ferritisation method. The possibility of obtaining Ni-Cu-Zn ferrites by processing of galvanic sludge based on of ferritization technology has been studied. Influence of different technological parameters and activation methods of the ferritisation process: thermal and electromagnetic pulse at temperatures of 75°С and 20°С, respectively, on qualitative and quantitative phase content of ferrite sediments has been experimentally determined. The method of electromagnetic pulse activation provides the appropriate degree of heavy metal ions extraction – 99.96%, and also has undeniable energy advantages over thermal, since energy consumption is reduced more than 60%. The efficiency of electromagnetic pulse discharges with magnetic induction amplitude of 0.298 T and a pulse frequency from 0.5 to 10 Hz to obtain environmentally friendly ferrite precipitates has been confirmed. The use of Ni-Cu-Zn ferrite powder for production of coatings that shield the electromagnetic rays in the ultrahigh frequency range is proposed. Obtained sediments have maximum content of crystalline ferromagnetic phases of ferrites – more than 93%. The proposed resource-saving ferritisation process prevents environmental pollution, ensures efficient and rational use of raw materials and energy in industry, as well as allows to obtain marketable products from industrial waste.

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Che, Ru Xin, Bing Yu, and Chun Xia Wang. "Preparation and Magnetic Properties of the Core-Nanoshell Composite Materials Doped with Sm." Materials Science Forum 694 (July 2011): 461–65. http://dx.doi.org/10.4028/www.scientific.net/msf.694.461.

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The core-nanoshell composite materials doped with Sm were prepared by a solid-state reaction method. The core is magnetic fly-ash hollow cenosphere, and the shell is the nanosized ferrite doped with Sm. The thermal decomposition process of the sample was investigated by thermogravimetric analysis-differential scanning calorimetry ( TG- DSC ). The morphology and composition of the composite materials were investigated by the X-ray diffraction analysis ( XRD ), scanning electron microscope ( SEM ) and energy disperse spectroscopy ( EDS ). The results of vibrating sample magnetometer analysis ( VSM ) indicated that the exchange-coupling interaction happens between ferrite of magnetic fly-ash hollow cenosphere and nanosized ferrite coating, which caused outstanding magnetic properties. The results show that doped with Sm can enhance the coercivity too, so the magnetic properties could be promoted further by the adjustment of compositions and the use of special techniques. The magnetic properties of the core-nanoshell composite material are better than that of single-phase.

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40

Elsayed, Elsayed M., Hazem F. Khalil, Ibrahim A. Ibrahim, Mostafa R. Hussein, and Mohamed M. B. El-Sabbah. "The Significance of Buffer Solutions on Corrosion Processes of Cobalt Ferrite CoFe2O4 Thin Film on Different Substrates." Combinatorial Chemistry & High Throughput Screening 23, no. 7 (October 5, 2020): 599–610. http://dx.doi.org/10.2174/1386207323666191217130209.

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Background: The spinel ferrite nanoparticles, such as zinc, nickel, and cobalt ferrites have exceptional electronic and magnetic properties. Cobalt ferrite nanomaterial (CoFe2O4) is a hard material that reveals high magnetic, mechanical, and chemical stability. Aim and Objective: The objective of this research is to predict the corrosion behavior of cobalt ferrite (CoFe2O4) thin films deposited on different substrates (platinum Pt, stainless steel S.S, and copper Cu) in acidic, neutral, and alkaline medium. Materials and Method: Cobalt ferrite thin films were deposited on platinum, stainless steel, and copper via electrodeposition-anodization process. After that, corrosion resistance of the prepared nanocrystalline cobalt ferrite on different substrates was investigated in acidic, neutral, and alkaline medium using open circuit potential and potentiodynamic polarization measurements. The crystal structure, crystallite size, microstructure, and magnetic properties of the ferrite films were investigated using a combination of XRD, SEM and VSM. Results: The results of XRD revealed a cubic spinel for the prepared cobalt ferrite CoFe2O4. The average size of crystallites was found to be about 43, 77, and 102 nm precipitated on platinum, stainless steel, and copper respectively. The magnetic properties of which were enhanced by rising the temperature. The sample annealed at 800oC is suitable for practical application as it showed high magnetization saturation and low coercivity. The corrosion resistance of these films depends on the pH of the medium as well as the presence of oxidizing agent. Conclusion: Depending on the obtained corrosion rate, we can recommend that, CoFe2O4 thin film can be used safely in aqueous media in neutral and alkaline atmospheres for Pt and Cu substrates, but it can be used in all pH values for S.S. substrate.

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41

Thomas, Tina, Marius van Dijk, Marc Dreissigacker, Stefan Hoffmann, Hans Walter, Karl-Friedrich Becker, and Martin Schneider-Ramelow. "Ferrites in Transfer-Molded Power SiPs: Challenges in Packaging." Journal of Microelectronics and Electronic Packaging 17, no. 2 (April 1, 2020): 35–44. http://dx.doi.org/10.4071/imaps.1064487.

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Abstract Transfer-molding process is enjoying growing interest when aiming for novel high-power density system-in-packages (power SiPs), where not only transistors and diodes but also drivers, passives, coils, and transformers are supposed to be integrated in one package. Encapsulating modules in a transfer-molding process induces higher mechanical load onto module components compared with conventional silicone potting. Previous investigations have shown that integration of delicate components as ferrite cores into molded packages is not as trivial as integration of conventional surface-mount devices or power semiconductors; the brittle ferrites tend to fracture during the encapsulation process, resulting in higher ferrite core loss. The current study aims to identify main root causes for ferrite core cracking during manufacturing of molded power SiPs. The test vehicle is a symmetrical printed circuit board–based package with three pairs of E-shaped ferrite cores. The epoxy molding compound deployed here is characterized to enable filling simulations. Because technical datasheets of ferrites typically lack specifications of mechanical properties, ferrite materials are analyzed in more detail. Filling simulations and thermomechanical simulations are performed to gain insight into process-induced stress, which may induce cracks in the ferrites. In addition, different ferrite designs are evaluated regarding core losses and mechanical stability and, thus, their tendency to fracture.

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Gofur, Abdul, Alamgir Hossain, Shibendra Shekher Sikder, and Dilip Kumar Saha. "Synthesis and Characterization of B2O3Additive on Ni-Cu-Zn ferrites by Solid State Reaction Method." European Journal of Engineering Research and Science 2, no. 9 (September 30, 2017): 54. http://dx.doi.org/10.24018/ejers.2017.2.9.439.

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Ni-Cu-Zn ferrites are well-known technological magnetic materials used for manufacturing of multilayer chip inductor and applications in various electrical devices. The work is focused on the persuade of substitutions and sintering additive B2O3 on structural, transport and electromagnetic properties of Ni-Cu-Zn ferrites. The composition Ni0.28Cu0.10Zn0.62Fe2O4 + x wt. % where x= 0.2 to 0.8 for V2O5 was prepared by using the solid state reaction technique sintered at 1200oC with 6 hours holding time. Lattice parameters of Ni0.28Cu0.10Zn0.62Fe2O4 + x wt. % Bi2O3 are slightly decrease with increase x content. The grain growth by increasing the additives Bi2O3 content inter diffusion as results after > 0.4wt. % Bi2O3 content abnormal grain growth. Curie temperature (Tc) decreases continuously with increase of doped Bi2O3 additives in ferrite samples. The magnetization process all the samples are soft magnetic behavior of magnetic materials. Initial permeability (µi) decreases with increasing doped Bi2O3 content in ferrite samples and hence the highest value of quality factor is found for x = 0.4 within the range 20 kHz to 2MHz. The µi shows the flat profile from 1 kHz to 4MHz indicating frequency stability for all the ferrite samples. The visible grain growth indicates the improved electromagnetic properties. DC resistivity decreases with increasing temperature shows the semiconducting nature of the sample. With increasing the frequency, the dielectric constant is found to decrease continuously and remain almost frequency independent at higher frequency range.

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Töpfer, J., S. Bierlich, S. Barth, B. Pawlowski, F. Bechtold, and J. M¨ller. "Z-, Y- and M-type Hexagonal Ferrites for High-Frequency Inductive Multilayer Devices." Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2011, CICMT (September 1, 2011): 000177–81. http://dx.doi.org/10.4071/cicmt-2011-wa21.

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Hexagonal ferrites can be used as soft magnetic materials for multilayer inductors for high frequency applications up to 3 GHz. We report on the preparation, thermal stability and magnetic properties of Z-, Y- and M-type hexagonal ferrites. Co2Z-type ferrite Ba3Co2Fe24O41 and iron excess Ba3Co2−yFe24+yO41 (0 ≤ y ≤ 0.8) were prepared by the mixed oxide route. Single phase Z-type ferrites were obtained after sintering at 1300°C. The permeability of a sample with y = 0.6 sintered at 1300°C is μ = 30 with a resonance frequency of 1 GHz. The addition of Bi2O3 as sintering aid shifts the maximum shrinkage down to 950°C and dense samples were sintered at 950°C; however, their permeability is only μ = 3…5. It is shown that Co2Z ferrites are not stable under LTCC conditions. Cu-substituted Z-type ferrites Ba3Co2-xCuxFe24O41 exhibit enhanced sintering ability, but sintering at 950°C also results in low permeability. Y-type hexagonal ferrites Ba2Co2−x−yZnxCuyFe12O22 were prepared at 1100°C and a permeability of μ = 20 was found for x = 1.2 and y = 0.8. Samples with Bi2O3 addition were sintered at 950 and 900°C exhibiting a permeability of μ = 10. Similar values were measured for M-type ferrites BaFe12-2yCoyTiyO19 with y = 1.2 which were sintered at 900°C using additives. Co/Ti co-substitution is an essential prerequisite for tailoring the magneto-crystalline anisotropy. Co/Ti- substituted M-type materials are stable under LTCC conditions. Ferrite multilayer devices were fabricated by screen printing coils onto ferrite tapes, stacking and lamination. Firing was performed between 1300°C and 900°C, i.e. at HTCC and LTCC conditions, respectively. The inductance behavior of the devices was evaluated and modeled. It is shown that hexagonal ferrites are suitable materials for the high-frequency multilayer inductors; however, Y- and M-type ferrites are preferred for LTCC-type inductors cofired at 900°C with Ag metallization.

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Sarkar, Kakali, Soumya Mukherjee, and Siddhartha Mukherjee. "Structural, electrical and magnetic behaviour of undoped and nickel doped nanocrystalline bismuth ferrite by solution combustion route." Processing and Application of Ceramics 9, no. 1 (2015): 53–60. http://dx.doi.org/10.2298/pac1501053s.

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Multiferroic bismuth ferrite (BFO) and Ni-doped bismuth ferrites, with perovskite structure, were synthesized by chemical route at the temperatures ranging from 500 to 600 ?C in controlled atmosphere. The structural phase analysis of materials was identified by XRD and crystallite size was calculated from the half width measurement of the well defined major XRD diffraction peak. Average crystallite size was calculated by applying Scherrer?s formula and found to have values in the range from 14 to 35 nm. FESEM was used to evaluate the morphology and structural formation of nanocrystallite grains, while EDX confirmed elemental composition including the presence of dopant in the matrix. Dielectric properties and effect of electric field on polarization behaviour were studied for both undoped and Ni-doped BFO. Doping shows a clear change in ferroelectric behaviour. Antiferromagnetic nature of bulk bismuth ferrite transforms to superparamagnetic strong ferroelectric nature for both undoped and nickel doped nanocrystalline bismuth ferrite due to its close dimension of crystallite size with magnetic domains leading to break-down of frustrated spin cycloidal moment. The superparamagnetism behaviour is more pronounced for the nickel doped BFO though magnetic saturation is slightly higher for the undoped nanocrystalline bismuth ferrite.

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45

Zhang, Bianfang, Guide Tang, Zonglin Yan, Zhenbiao Wang, Qingfen Yang, and Jianpo Cui. "Synthesis of magnetic manganese ferrite." Journal of Wuhan University of Technology-Mater. Sci. Ed. 22, no. 3 (September 2007): 514–17. http://dx.doi.org/10.1007/s11595-006-3514-3.

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bin Zahari, Muhammad Hanif, Beh Hoe Guan, Lee Kean Chuan, and Afiq Azri bin Zainudin. "Structural, Morphological and Magnetic Characterization of Sm-substituted Ni-Zn Ferrite." Nanoscience & Nanotechnology-Asia 10, no. 2 (February 25, 2020): 152–56. http://dx.doi.org/10.2174/2210681208666181018093813.

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Background: Rare earth materials are known for its salient electrical insulation properties with high values of electrical resistivity. It is expected that the substitution of rare earth ions into spinel ferrites could significantly alter its magnetic properties. In this work, the effect of the addition of Samarium ions on the structural, morphological and magnetic properties of Ni0.5Zn0.5SmxFe2-xO4 (x=0.00, 0.02, 0.04, 0.06, 0.08, 0.10) synthesized using sol-gel auto combustion technique was investigated. Methods: A series of Samarium-substituted Ni-Zn ferrite nanoparticles (Ni0.5Zn0.5SmxFe2-xO4 where x=0.00, 0.02, 0.04, 0.06, 0.08, 0.10) were synthesized by sol-gel auto-combustion technique. Structural, morphological and magnetic properties of the samples were examined through X-Ray Diffraction (XRD), Field-Emission Scanning Electron Microscope (FESEM) and Vibrating Sample Magnetometer (VSM) measurements. Results: XRD patterns revealed single-phased samples with spinel cubic structure up to x= 0.04. The average crystallite size of the samples varied in the range of 41.8 – 85.6 nm. The prepared samples exhibited agglomerated particles with larger grain size observed in Sm-substituted Ni-Zn ferrite as compared to the unsubstituted sample. The prepared samples exhibited typical soft magnetic behavior as evidenced by the small coercivity field. The magnetic saturation, Ms values decreased as the Sm3+ concentration increases. Conclusion: The substituted Ni-Zn ferrites form agglomerated particles inching towards more uniform microstructure with each increase in Sm3+ substitution. The saturation magnetization of substituted samples decreases with the increase of samarium ion concentration. The decrease in saturation magnetization can be explained based on weak super exchange interaction between A and B sites. The difference in magnetic properties between the samples despite the slight difference in Sm3+ concentrations suggests that the properties of the NiZnFe2O4 can be ‘tuned’, depending on the present need, through the substitution of Fe3+ with rare earth ions.

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Kračunovská, Silvia, and Joerg Töpfer. "Co₂Z, Co₂Y and CoM-Type Hexagonal Ferrites for Multilayer Inductors." Key Engineering Materials 434-435 (March 2010): 361–65. http://dx.doi.org/10.4028/www.scientific.net/kem.434-435.361.

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Abstract. Hexagonal Co-containing Z-; Y- and M-type ferrites are used as soft magnetic materials for multilayer inductors for operating frequencies up to 3 GHz. Co2Z-type Ba3Co2Fe24O41, iron excess Ba3Co2-yFe24+yO41 (0  y  0.8) and Ba3Co2-CuxFe24O41 (0  x  1.0) ferrites have their stability intervals between 1260-1350°C. The permeability of a ferrite with y = 0.6 sintered at 1300°C is µ = 30 throughout the MHz. Addition of Bi2O3 shifts the maximum shrinkage down to 950°C. Their permeability is µ = 5 because of partial decomposition of the Co2Z phase. Y-type ferrite Ba2Co1.2-xZnxCu0.8Fe12O22 (x = 1.2) sintered at 1100°C shows a permeability of µ = 20. Sintering at 900°C reduces the permeability to µ = 10. M-type BaCo1.2Ti1.2Fe9.6O19 ferrites sintered at 970°C display a permeability of µ = 35.

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Mohapatra, Jeotikanta, Meiying Xing, and J. Ping Liu. "Inductive Thermal Effect of Ferrite Magnetic Nanoparticles." Materials 12, no. 19 (September 30, 2019): 3208. http://dx.doi.org/10.3390/ma12193208.

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Localized heat induction using magnetic nanoparticles under an alternating magnetic field is an emerging technology applied in areas including, cancer treatment, thermally activated drug release and remote activation of cell functions. To enhance the induction heating efficiency of magnetic nanoparticles, the intrinsic and extrinsic magnetic parameters influencing the heating efficiency of magnetic nanoparticles should be effectively engineered. This review covers the recent progress in the optimization of magnetic properties of spinel ferrite nanoparticles for efficient heat induction. The key materials factors for efficient magnetic heating including size, shape, composition, inter/intra particle interactions are systematically discussed, from the growth mechanism, process control to chemical and magnetic properties manipulation.

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Tsay, Chien-Yie, Yi-Chun Chiu, and Chien-Ming Lei. "Hydrothermally Synthesized Mg-Based Spinel Nanoferrites: Phase Formation and Study on Magnetic Features and Microwave Characteristics." Materials 11, no. 11 (November 14, 2018): 2274. http://dx.doi.org/10.3390/ma11112274.

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Three kinds of magnesium-based spinel nanoferrites with the chemical formulas of MgFe2O4 (Mg ferrite), Mg0.9Mn0.1Fe2O4 (Mg-Mn ferrite), and Mg0.9Mn0.1In0.1Fe1.9O4 (Mg-Mn-In ferrite) were synthesized by hydrothermal route. We report the composition-dependent magnetic parameters and microwave properties of Mg-based ferrite nanoparticles. XRD results revealed that the Mg-based ferrite nanoparticles exhibited a cubic spinel structure and had an average nanocrystallite size in the range of 5.8–2.6 nm. Raman spectroscopy analysis confirmed the formation of cubic-spinel phase Mg-based nanoferrites. The room-temperature magnetization measurements indicated that the Mg ferrite nanoparticles had superparamagnetic behavior; whereas the Mg-Mn and Mg-Mn-In ferrite nanoparticles exhibited a paramagnetic nature. The microwave properties of obtained ferrite nanoparticles were studied by alternating current (AC) magnetic susceptibility measurement and electron paramagnetic resonance (EPR) spectroscopy. It was found that the un-substituted Mg ferrite sample exhibited microwave characteristics better than those of the Mn substituted and Mn-In co-substituted Mg ferrite samples.

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Mohd Mokhtar, Nurul Afiqah, Hoe Guan Beh, and Kean Chuan Lee. "The Potential Application of MnZn Ferrite Nanofluids for Wettability Alteration and Oil-Water Interfacial Tension Reduction." Crystals 9, no. 12 (November 27, 2019): 626. http://dx.doi.org/10.3390/cryst9120626.

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Recently, a non-invasive method of injecting magnetic/dielectric nanofluids into the oil reservoir was used for oil recovery application. The use of magnetic nanofluids in Enhanced Oil Recovery (EOR) has been reported to improve oil recovery. It is believed that the magnetic properties of nanoparticles (NPs) have a direct influence on the viscosity and wettability of nanofluid, and on oil-water interfacial tension (IFT). Thus, Mn0.5Zn0.5Fe2O4 (MnZn) ferrites may be a good candidate to be used in nanofluids for wettability alteration and oil-water IFT reduction due to their excellent magnetic properties, such as a high initial permeability and low magnetic losses. Therefore, this work investigated the potential of MnZn ferrite NPs to alter viscosity, wettability, and oil-water IFT. MnZn Ferrite NPs have been synthesized by a sol-gel auto-combustion process. The effects of calcination temperature varying from 300 °C to 700 °C on the phase formation, microstructures such as surface morphology, and magnetic characterizations were studied. MnZn ferrite nanofluids were prepared using synthesized MnZn NPs that dispersed into brine along with sodium dodecylbenzenesulfonate (SDBS) as a dispersant, and their effects on the wettability and oil-water IFT were studied. X-ray diffraction (XRD) measurements revealed that MnZn ferrite calcined at 300 °C and 400 °C were single phase. The average crystallite size calculated through Scherrer’s equation differed from 32.0 to 87.96 nm. The results showed that the nanofluid with MnZn particles calcined at 300 °C is the best nanofluid in terms of IFT reduction and base nanofluid’s wettability alteration. Moreover, the overall results proved that nanofluid with MnZn ferrite NPs can alter the wettability of base nanofluid, oil-nanofluid IFT, and nanofluid viscosity. This study provides insights towards a better understanding of the potential application of MnZn Ferrite nanofluids to Wettability Alteration and IFT Reduction in Enhanced Oil Recovery.

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Journal articles on the topic 'Ferrite (Magnetic materials)'

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