Journal articles: 'DMS [Diluted Magnetic Semiconductors]'

1

Samarth, N., and J. K. Furdyna. "Diluted Magnetic Semiconductors." MRS Bulletin 13, no. 6 (June 1988): 32–36. http://dx.doi.org/10.1557/s0883769400065477.

Full text

Abstract:

Diluted magnetic semiconductors (DMS) are semiconducting alloys whose lattice is partly made of substitutional magnetic ions. The most extensively studied materials of this type are the alloys, in which a fraction of the group II sublattice is replaced at random by Mn. The entire family of ternary alloys, along with their crystal structure and corresponding ranges of composition, is listed in Table I. Over the past decade, these alloys have attracted a growing scientific interest because of new fundamental effects in semiconductor physics and magnetism in these materials and because of their potential applications in optical nonreciprocal devices, solid state lasers, flat panel displays, infrared detectors, and other optoelectronic applications.The increasing popularity of this field can be attributed to the broad variety of fascinating problems offered by the study of the alloys. To begin with, there is an interest in the semiconducting properties per se — for instance, the understanding of the electronic band structure and its variation with alloy composition. As in other ternary alloys, the band parameters and the lattice constant can be “tuned” by controlling the alloy composition, opening the door to band-gap engineering and lattice matching in the context of epitaxially grown superlattices and het-erostructures. The random distribution of Mn atoms with a well-characterized antiferromagnetic Mn-Mn exchange interaction provides an ideal system for studying fundamental questions in disordered magnetism. The sp-d exchange interaction between the spins of band electrons and the localized moments of the Mn atoms constitutes a unique interplay between semiconductor physics and magnetism. This leads to unusual magneto-transport and magneto-optic phenomena such as an extremely large Faraday rotation, giant negative magneto-resistance, and a magnetic-field-induced metal-insulator transition. Finally, the potential technological importance of DMS is also being recognized. For example, the large Faraday rotation holds promise of DMS applications as optical isolators, modulators, and circulators. We will briefly introduce some of the exciting research problems offered by the study of DMS. More detailed information is available in several extensive reviews and compendia.

APA, Harvard, Vancouver, ISO, and other styles

2

CHOI, HEON-JIN, HAN-KYU SEONG, and UNGKIL KIM. "DILUTED MAGNETIC SEMICONDUCTOR NANOWIRES." Nano 03, no. 01 (February 2008): 1–19. http://dx.doi.org/10.1142/s1793292008000848.

Full text

Abstract:

An idea for simultaneously manipulating spin and charge in a single semiconductor medium has resulted in the development of diluted magnetic semiconductors (DMSs), which exhibits surprisingly room temperature ferromagnetic signatures despite having controversial ferromagnetic origin. However, achievement of truly room temperature ferromagnetism by carrier mediation is still the subject of intense research to develop the practical spin-based devices. Nanowires with one-dimensional nanostructure, which offers thermodynamically stable features and typically single crystalline and defect free, have a number of advantages over thin films with respect to studying ferromagnetism in DMSs. This review focuses primarily on our works on GaN -based DMS nanowires, i.e., Mn -doped GaN , Mn -doped AlGaN and Cu -doped GaN nanowires. These DMS nanowires have room temperature ferromagnetism by the local magnetic moment of doping elements that are in a divalent state and in tetrahedral coordination, thus substituting Ga in the wurtzite-type network structure of host materials. Importantly, our evidences indicate that the magnetism is originated from the ferromagnetic interaction driven by the carrier. These outcomes suggest that nanowires are ideal building blocks to address the magnetism in DMS due to their thermodynamic stability, single crystallinity, free of defects and free standing nature from substrate. Nanowires themselves are ideal building blocks for nanodevices and, thus, it would also be helpful in developing DMS-based spin devices.

APA, Harvard, Vancouver, ISO, and other styles

3

Stephanovich, V. A., and Yu G. Semenov. "The Magnetic Domain Structure Properties in Diluted Magnetic Semiconductors." Ukrainian Journal of Physics 65, no. 10 (October 9, 2020): 881. http://dx.doi.org/10.15407/ujpe65.10.881.

Full text

Abstract:

We present a comprehensive analysis of the domain structure formation in the ferromagneticphase of diluted magnetic semiconductors (DMS) of the p-type. Our analysis is carried outon the base of the effective magnetic free energy of DMS calculated by us earlier. This freeenergy, substituting DMS (a disordered magnet) by an effective ordered substance, permits usto apply the standard phenomenological approach to the domain structure calculation. Usingthe coupled system of Maxwell equations with those obtained by the minimization of the freeenergy functional, we show the existence of the critical ratio vcr of concentration of chargecarriers and magnetic ions such that the sample critical thickness Lcr (such that the sampleis monodomain at L < Lcr) diverges as v → vcr. At v > vcr, the sample is monodomain. Thisfeature makes DMS different from conventional ordered magnets, as it gives a possibility tocontrol the sample critical thickness and the emerging domain structure period by a variationof v. As the concentration of magnetic impurities grows, vcr → ∞, restoring a conventionalbehavior of ordered magnets. Above facts have been revealed by the examination of the tem-perature of the transition to an inhomogeneous magnetic state (stripe domain structure) inthe slab of a p-type DMS with finite thickness L. Our theory can be easily generalized for anarbitrary disordered magnet.

APA, Harvard, Vancouver, ISO, and other styles

4

MIURA, N., Y. H. MATSUDA, and T. IKAIDA. "MEGAGAUSS CYCLOTRON RESONANCE IN SEMICONDUCTOR NANOSTRUCTURES AND DILUTED MAGNETIC SEMICONDUCTORS." International Journal of Modern Physics B 16, no. 20n22 (August 30, 2002): 3399–404. http://dx.doi.org/10.1142/s0217979202014565.

Full text

Abstract:

We report the latest results of cyclotron resonance experiments on semiconductor nanostructures and diluted magnetic semiconductors (DMS) in very high magnetic fields up to 600 T produced by magnetic flux compression and the single turn coiled technique. Many new features were observed in the very high field range, such as characteristic behavior of low dimensional electrons, carrier dynamics or electron-electron interaction effects in quantum wells and quantum dot samples. In PbSe/PdEuTe quantum dots, which were regularly arranged to form an fcc superlattice, we observed an absorption peak with a splitting and a wavelength dependence of the absorption intensity. In DMS, such as CdMnTe and InMnAs, change of the carrier effective mass with Mn doping was studied in detail. We found anomalous mass increase with doping of magnetic ions. The amount of the observed mass increase cannot be explained by the k·p theory and suggests the importance of d-s or d-p hybridization.

APA, Harvard, Vancouver, ISO, and other styles

5

Ionescu, M., P. Photongkam, R. Siegele, A. Deslantes, S. Li, and D. D. Cohen. "Fabrication and Characterisation of Diluted Magnetic Semiconductors Thin Films Using Ion Beams." Materials Science Forum 706-709 (January 2012): 2869–73. http://dx.doi.org/10.4028/www.scientific.net/msf.706-709.2869.

Full text

Abstract:

The intrinsic n-type (II-VI) semiconductor ZnO may become ferromagnetic at room temperature, by small additions of magnetic ions, resulting in what is called a Diluted Magnetic Semiconductors (DMS). The potential application of DMS in spintronic devices of is driving the research effort to dope magnetic elements into this semiconductors with a depth distribution as uniform as possible. The doping levels and the depth distribution of dopants are critical parameters for the magnetic properties of this material and the possible clustering of dopants can play a significant negative role in its macroscopic magnetic properties. Thin ZnO (0001) films of between 100nm and 500nm, grown on c-Al2O3 by MOCVD were implanted with Co, Eu and Co+Eu by ion irradiation at low energies. In order to improve the depth distribution of dopants, the ion implantation was carried out through a number of appropriately chosen range foils. The results show an increase in the level of dopant homogeneity throughout the entire thickness of the film, and a ferromagnetic behavior above room temperature for Zn0.96Co0.04O, Zn0.96Eu0.04O and Zn0.92Co0.04Eu0.04O.

APA, Harvard, Vancouver, ISO, and other styles

6

HOANG, ANH TUAN, and DUC ANH LE. "OPTICAL CONDUCTIVITY OF (III, Mn)V DILUTED MAGNETIC SEMICONDUCTORS." Modern Physics Letters B 21, no. 02n03 (January 30, 2007): 69–77. http://dx.doi.org/10.1142/s0217984907012591.

Full text

Abstract:

The coherent potential approximation (CPA) is used on a minimal model of diluted magnetic semiconductors (DMS), where the carrier feels a nonmagnetic potential at a magnetic impurity site, and its spin interacts with the localized spins of the magnetic impurities through exchange interactions. The CPA equations for one particle Green function are derived and the optical conductivity dependence on the system parameters and temperature is investigated. For illustration, the case of Ga 1-x Mn x As is considered and compared with experimental data.

APA, Harvard, Vancouver, ISO, and other styles

7

Rivera, S. A. López. "New Results in Raman Scattering in Diluted Magnetic Semiconductors (DMS)." Japanese Journal of Applied Physics 32, S3 (January 1, 1993): 403. http://dx.doi.org/10.7567/jjaps.32s3.403.

Full text

APA, Harvard, Vancouver, ISO, and other styles

8

Gama, Lucianna, M. A. Ribeiro, Débora A. Vieira, A. M. C. Santos, Ruth Herta Goldsmith Aliaga Kiminami, I. T. Weber, and Ana Cristina Figueiredo de Melo Costa. "Synthesis Methods Evaluation for Preparation of the Zno:Co Diluted Magnetic Semiconductor (DMS)." Materials Science Forum 591-593 (August 2008): 387–91. http://dx.doi.org/10.4028/www.scientific.net/msf.591-593.387.

Full text

Abstract:

Diluted magnetic semiconductors (DMS), which have both semiconducting and magnetic properties, are those in which transitions metal ions substitute cations of host semiconductor materials [1]. There is a great interest for DMS for use as the material of spintronics. In this study is reported the structural and morphologic characterization of Zn1.95Co0.05O nanoparticles obtained by Pechini method and combustion reaction. The powders resulting were characterized by X-ray diffraction (XRD) for determination of the phases, crystalline phase and lattice parameter; nitrogen adsorption by BET for determination of the specific superficial area and calculation the particle size from the superficial area and scanning electron microscopy (SEM) for morphologic analysis. The XRD results demonstrated the viability of obtaining crystalline and nanosize powders by the both synthesis routes. For all samples the average crystallite sizes was nanosized, but the powders obtained by reaction combustion is smaller. The SEM micrographs shows that the powders obtained for both syntheses are constituted of soft agglomerates.

APA, Harvard, Vancouver, ISO, and other styles

9

CROOKER, SCOTT A., and NITIN SAMARTH. "TUNING MAGNETIC DISORDER IN DILUTED MAGNETIC SEMICONDUCTORS USING HIGH FIELDS TO 89 TESLA." International Journal of Modern Physics B 23, no. 12n13 (May 20, 2009): 2575–84. http://dx.doi.org/10.1142/s0217979209062013.

Full text

Abstract:

We describe recent and ongoing studies at the National High Magnetic Field Laboratory at Los Alamos using the new "100 Tesla Multi-Shot Magnet", which is presently delivering fields up to ~89 T during its commissioning. We discuss the first experiments performed in this magnet system, wherein the linewidth of low-temperature photoluminescence spectra was used to directly reveal the degree of magnetic alloy disorder 'seen' by excitons in single Zn 0.80 Cd 0.22 Mn 0.08 Se quantum wells. The magnetic potential landscape in II-VI diluted magnetic semiconductors (DMS) is typically smoothed when the embedded Mn 2+ spins align in an applied field. However, an important (but heretofore untested) prediction of current models of compositional disorder is that magnetic alloy fluctuations in many DMS compounds should increase again in very large magnetic fields approaching 100 T. We observed precisely this increase above ~70 T, in agreement with a simple model of magnetic alloy disorder.

APA, Harvard, Vancouver, ISO, and other styles

10

HOANG, ANH-TUAN. "CURIE TEMPERATURE OF THE TWO-BAND MODEL FOR DILUTED MAGNETIC SEMICONDUCTORS IN COHERENT POTENTIAL APPROXIMATION." Modern Physics Letters B 23, no. 26 (October 20, 2009): 3171–77. http://dx.doi.org/10.1142/s021798490902120x.

Full text

Abstract:

Coherent potential approximation (CPA) is extended to a two-band model for diluted magnetic semiconductors (DMS). The magnetic transition temperature Tc as a function of magnetic coupling constants, hopping parameters and carrier densities is calculated by minimizing the free energy of the coupled carrier-localized spin system. It is shown that Tc can be substantially raised by considering multiband systems.

APA, Harvard, Vancouver, ISO, and other styles

11

Jiang, Ying, and Yong Wang. "Mn-Rich Nanostructures inGe1-xMnx: Fabrication, Microstructure, and Magnetic Properties." Advances in Materials Science and Engineering 2012 (2012): 1–18. http://dx.doi.org/10.1155/2012/726921.

Full text

Abstract:

Magnetic semiconductors have attracted extensive attention due to their novel physical properties as well as the potential applications in future spintronics devices. Over the past decade, tremendous efforts have been made in the diluted magnetic semiconductors (DMS) system, with many controversies disentangled but many puzzles unsolved as well. Here in this paper, we summarize recent experimental results in the growth, microstructure and magnetic properties of Ge-based DMSs (mainlyGe1-xMnx), which have been comprehensively researched owing to their compatibility with Si microelectronics. Growth conditions of high-quality, defect-free, and magneticGe1-xMnxbulks, thin films, ordered arrays, quantum dots, and nanowires are discussed in detail.

APA, Harvard, Vancouver, ISO, and other styles

12

Thai, Vu Kim, and Hoang Anh Tuan. "Two Band Model for Diluted Magnetic Semiconductors: Study of the Ferromagnetic Transition Temperature." Communications in Physics 21, no. 2 (June 28, 2011): 125. http://dx.doi.org/10.15625/0868-3166/21/2/106.

Full text

Abstract:

The ferromagnetic transition temperature (Tc) of a two band model for diluted magnetic semiconductors (DMS) is calculated by using the coherent potential approximation (CPA). It is shown that Tc is strongly parameter dependent on density of the carriers, magnetic coupling constants, and the hopping terms. The maximal Tc of the two band model is found when both impurity bands fully overlap and this value is approximately twice larger than the highest Tc obtained in the single band model.

APA, Harvard, Vancouver, ISO, and other styles

13

Semenov, Yu G., and S. M. Ryabchenko. "Molecular-Field Approximation in the Theory of Ferromagnetic Phase Transition in Diluted Magnetic Semiconductors." Ukrainian Journal of Physics 66, no. 6 (July 6, 2021): 503. http://dx.doi.org/10.15407/ujpe66.6.503.

Full text

Abstract:

In this pedagogical paper, the comparative analysis of two common approaches describing the ferromagnetic phase transition in diluted magnetic semiconductors (DMS) is expounded in terms of the Weiss field approximation. Assuming a finite spin polarization of the magnetic ions, the treatment of carrier-ion exchange interaction in the first order evokes a homogeneous Weiss molecular field that polarizes the spins of free carriers. In turn, this spin polarization of the free carriers exerts the effective field that may stabilize the DMS spin polarization belowa critical temperature TC. The treatment of such self-consistent spontaneous DMS magnetization can be done in terms of the spin-spin interaction independent of the inter-ion distance and the infinitesimal in thermodynamic limit. On the other hand, by additionally accounting for the second-order effects of the carrier-ion exchange interaction, we can treat a Weiss field in terms of the Ruderman–Kittel–Kasuya–Yosida indirect spin-spin interaction, which oscillates and does not disappear at finite inter-ion distances in the case of a finite concentration of carriers. These both approaches result in the same Curie temperature TC provided a non-correlated homogeneous random distribution of the localized spin moments over the sample volume. We discuss the origin of such coincidence and show when this is not a case in other more realistic models of the conducting DMSs.

APA, Harvard, Vancouver, ISO, and other styles

14

KIM, H. J., and K. S. YI. "MAGNETIZATION OF DIGITALLY Mn-DOPED DILUTED MAGNETIC SEMICONDUCTOR QUANTUM WELLS." International Journal of Modern Physics B 18, no. 27n29 (November 30, 2004): 3757–60. http://dx.doi.org/10.1142/s0217979204027414.

Full text

Abstract:

We present spin-resolved electronic properties of digitally Mn -doped diluted magnetic semiconductor (DMS) quantum wells (QWs) with an emphasis on the control of spontaneous magnetization and spin carrier distributions in terms of QW structure parameters and doping profiles of the magnetic ions. A combined Schrödinger and Poisson equation is solved numerically to obtain self-consistent subband wavefunctions and energies of the holes in the DMS QWs. Self-consistent spin-resolved subband structure shows that (i) the spatial distributions of the majority and minority spin carriers are separated in the DMS QW below the Curie temperature and (ii) the spontaneous magnetization of the Mn -doped magnetic nanostructure depends sensitively on doping profiles of the magnetic ion and the strength of exchange couplings.

APA, Harvard, Vancouver, ISO, and other styles

15

KIM, NAMMEE, T. W. KANG, and HEESANG KIM. "CONTROLLABLE SPIN POLARIZATION IN A DMS QUANTUM DOT." Modern Physics Letters B 19, no. 27 (November 30, 2005): 1419–27. http://dx.doi.org/10.1142/s0217984905009353.

Full text

Abstract:

The effects of electro-magnetic confining potentials and the s–d exchange interaction between substituted Mn ions and carriers on the spin polarization of carriers in an diluted magnetic semiconductor quantum dot are investigated within the framework of the effective-mass theory. The energy eigenvalues and wavefunctions of a single electron in the presence of an external magnetic field are studied by solving the one particle Schrödinger equation including the conventional Zeeman effect, the s–d exchange interaction and the electric confining potential which describes the dot. The eigenenergy structure for low lying states is strongly dependant on the relative sizes of the s–d exchange interactions and the conventional Zeeman energy splitting. When the spin splitting exceeds the cyclotron energy splitting, the Landau level overlappings occur so that the spin polarization of carriers is induced in low lying energy states. This spin polarization of carriers in the diluted magnetic semiconductor quantum dot can be controlled by changing the electro-magnetic confining potentials.

APA, Harvard, Vancouver, ISO, and other styles

16

SOUMA, SATOFUMI, SEUNG JOO LEE, and TAE WON KANG. "NUMERICAL STUDY OF FERROMAGNETISM IN DILUTED MAGNETIC SEMICONDUCTOR QUANTUM-WELLS." International Journal of Modern Physics B 19, no. 19 (July 30, 2005): 3151–60. http://dx.doi.org/10.1142/s0217979205031973.

Full text

Abstract:

We study the ferromagnetism in III-V diluted magnetic semiconductor (DMS) quantum-wells theoretically and numerically taking into account the occupation of multiple subbands by holes in quantum wells. Starting from the mean-field theory of carrier-induced ferromagnetism in III-V DMS along with the exchange-correlation interaction of holes within the local spin density approximation, we found that the ferromagnetic transition temperature Tc of DMS quantum-wells exhibits step-function-like dependence on the hole density, reflecting the quasi-two-dimensional nature of systems. Moreover, the temperature dependence of the spin polarization shows quite distinct characteristics depending on the hole density.

APA, Harvard, Vancouver, ISO, and other styles

17

Kamran, Muhammad Arshad, Bingsuo Zou, Kang Zhang, Xiongtao Yang, Fujian Ge, Lijie Shi, and Thamer Alharbi. "Dual-Color Lasing Lines from EMPs in Diluted Magnetic Semiconductor CdS:NiI Structure." Research 2019 (October 29, 2019): 1–15. http://dx.doi.org/10.34133/2019/6956937.

Full text

Abstract:

Have one ever seen a semiconductor that can issue two-color lasing lines? The diluted magnetic semiconductor (DMS) can do this. Here, we have observed dual lasing lines of 530 nm and 789 nm from a DMS structure of CdS:NiI, in which the excitonic magnetic polaron (EMP) and localized excitonic magnetic polaron (LEMP) are excitations out of ferromagnetic (NiS)x nanocluster and NiI2 nanoclusters within CdS lattice; both of them could lead to the collective EMP state at high excitation and therein produce coherent emission lines simultaneously. This occurrence is due to the superposition of EMP near CdS bandedge and the combination of the charge-transfer band of (NiI)n cluster with the LEMP within CdS lattice by overcoming the strong electron correlation of NiI cluster in a DMS structure, evidenced also by ab initio calculation. This finding opens a way to understand the collective behaviour of spin-coupled excitons in DMS and to find novel applications in the spin-related quantum technology.

APA, Harvard, Vancouver, ISO, and other styles

18

Hou, Qingyu, Chunwang Zhao, and Lingfeng Qu. "Effects of V heavy doping on the magnetic and optical properties in anatase TiO2." International Journal of Modern Physics B 31, no. 01 (January 10, 2017): 1650240. http://dx.doi.org/10.1142/s0217979216502404.

Full text

Abstract:

A half-metal diluted magnetic semiconductor (DMS) can be formed in heavy V-doped TiO2. Contradictory experimental results in the literature have reported about the absorption spectra blueshift and redshift results in heavy V-doped TiO2. This study aims to reveal the mechanism of half-metal DMS in heavy V-doped TiO2 and solve the problem of absorption spectra blueshift and redshift in the doping system. In this study, models of the unit cells of pure anatase TiO2 and two V heavy-doped supercells of Ti[Formula: see text]V[Formula: see text]O2 and Ti[Formula: see text]V[Formula: see text]O2 were constructed based on density functional theory, which uses the first-principles plane-wave ultrasoft pseudopotential method. All models were obtained through geometry optimization. Local density approximation [Formula: see text] was used to calculate the band structure, density of states (DOS), orbital charge and absorption spectrum of the doping system. The calculated results under the condition of electron spin showed that in the heavy doping concentration range, the volume of supercells increases, the total energy and formation energy decrease and the stability of the supercells increases as V doping concentration increases. Furthermore, the interaction of [Formula: see text]–[Formula: see text] states is weaker than that of [Formula: see text]–[Formula: see text] states, which results in the valence band maximum shifting toward the low-energy region, and also the optical bandgap becomes narrower as well as the redshift and intensity of the absorption spectrum become more notable. Noticeably, the hybrid coupling effect of Ti-3[Formula: see text] and V-3[Formula: see text] states becomes stronger, and the magnetic moment increases. The Fermi levels of spin-up band structure within the conduction band, which form the [Formula: see text]-type degenerate semiconductors, and the Fermi levels of spin-down band structure within the bandgap indicate that the doping system has semiconductor features. Therefore, V-doped anatase TiO2 is an extremely promising DMS because of its high electron polarizability of nearly 100%. The calculation results are consistent with the experimental data; these results explain the problems reasonably and adequately. Therefore, the research findings can help solve the contradiction of the redshift and blueshift in the preparation of photocatalysts and half-metal diluted magnetic semiconductors of V heavy-doped anatase TiO2.

APA, Harvard, Vancouver, ISO, and other styles

19

Torquato, R. A., S. E. Shirsath, R. H. G. A. Kiminami, and A. C. F. M. Costa. "Synthesis and structural, magnetic characterization of nanocrystalline Zn1-xCoxO diluted magnetic semiconductors (DMS) synthesized by combustion reaction." Ceramics International 44, no. 4 (March 2018): 4126–31. http://dx.doi.org/10.1016/j.ceramint.2017.11.213.

Full text

APA, Harvard, Vancouver, ISO, and other styles

20

Jacak, L., J. Krasnyj, D. Jacak, R. Gonczarek, M. Krzyżosiak, and P. Machnikowski. "Spin-Based Quantum Information Processing in Magnetic Quantum Dots." Open Systems & Information Dynamics 12, no. 02 (June 2005): 133–41. http://dx.doi.org/10.1007/s11080-005-5724-0.

Full text

Abstract:

We define the qubit as a pair of singlet and triplet states of two electrons in a He-type quantum dot (QD) placed in a diluted magnetic semiconductor (DMS) medium. The molecular field is here essential as it removes the degeneracy of the triplet state and strongly enhances the Zeeman splitting. Methods of qubit rotation as well as two-qubit operations are suggested. The system of a QD in a DMS is described in a way which allows an analysis of the decoherence due to spin waves in the DMS subsystem.

APA, Harvard, Vancouver, ISO, and other styles

21

Wang, Shiwei, Weiqiang Bo, Min Zhong, Cong Liu, Ying Li, Mingyuan Zhu, Yemin Hu, and Hongmin Jin. "Effect of Cr Content on the Properties of Magnetic Field Processed Cr-Doped ZnO-Diluted Magnetic Semiconductors." Journal of Nanomaterials 2012 (2012): 1–7. http://dx.doi.org/10.1155/2012/501069.

Full text

Abstract:

Cr-doped ZnO-diluted magnetic semiconductor (DMS) nanocrystals with various Cr contents were synthesized by hydrothermal method under high magnetic field. The result indicated that both the amount of Cr contents and high magnetic field significantly influenced crystal structure, morphology, and magnetic property of Cr-doped ZnO DMSs. When the Cr contents increased from 1 at% to 5 at%, the morphology of grains sequentially changed from flower-like to rod-like and then to the flake-like form. All the samples remained hexagonal wurtzite structure after Cr ions were doped into the ZnO crystal lattice. The Cr doping led to the increasing amount of defects and even enhanced the magnetic property of the matrix materials. All the Cr-doped ZnO DMSs obtained under high magnetic field exhibited obvious ferromagnetic behavior at room temperature. The results have also shown the successful substitution of the Cr3+ions for the Zn2+ions in the crystal lattice.

APA, Harvard, Vancouver, ISO, and other styles

22

GNANASEKAR, K., and K. NAVANEETHAKRISHNAN. "ELECTRICALLY TUNABLE "RENORMALIZATION" OF s–d EXCHANGE INTERACTION IN A DILUTED MAGNETIC SEMICONDUCTOR QUANTUM DOT." International Journal of Nanoscience 06, no. 01 (February 2007): 71–76. http://dx.doi.org/10.1142/s0219581x07004961.

Full text

Abstract:

We theoretically demonstrate that how the Rashba spin–orbit interaction induced by the external electric field can be used to manipulate spin degree of freedom of electrons in a diluted magnetic semiconductor quantum dot (DMS QD) in the presence of a weak perpendicular magnetic field. The effects of Rashba spin–orbit interaction, induced by the electrostatic potential, on the apparent total spin splitting in a diluted magnetic semiconductor quantum dot have been studied. We propose that the apparent total spin splitting is the result of electrically tunable "renormalization" of s–d exchange interaction. It could be favorably engineered to electrically tune the spin degree of freedom in the spintronic devices.

APA, Harvard, Vancouver, ISO, and other styles

23

Malik, Samiksha, Komal Mohite, Pranav Naik, and R. B. Tangsali. "Preparation, Characterization, Electrical and Magnetic Properties of Mn-Doped Dilute Magnetic Semiconductors." International Journal of Nanoscience 15, no. 05n06 (October 2016): 1660004. http://dx.doi.org/10.1142/s0219581x16600048.

Full text

Abstract:

Nanoparticle dilute magnetic semiconductors (DMS) are becoming increasingly important due to their possible applications in spintronics, an emerging field where the conduction process in the materials is a spin-based process. Nanoparticles of Mn-doped ZnO (DMS) material with general formula Zn[Formula: see text]MnxO ([Formula: see text]) were prepared by opting single stage combustion synthesis process. The samples characterized, exhibited formation of monophasic nanoparticles of the sample with average particle size ranging between 17 nm to 23 nm. The calculations of energy bandgap made from UV absorption spectra showed variation of the bandgap from 2.18 eV to 2.32 eV. The magnetic measurements (VSM) made on the samples confirmed formation of a single diamagnetic (Zn[Formula: see text]Mn[Formula: see text]) and two namely (Zn[Formula: see text]Mn[Formula: see text]) (Zn[Formula: see text]Mn[Formula: see text]) paramagnetic samples. It is interesting to see that all the three magnetic profiles exhibit hysteresis type behavior both in diamagnetic form and paramagnetic form. The resistivity of the samples was of the order of 10[Formula: see text] Ohm-cm ([Formula: see text]-cm) at lower temperatures. Temperature-dependent resistivity curves exhibited peaking behavior for all the three samples which is very interesting. Temperature-dependent thermo-power profiles give an indication of [Formula: see text]-type semiconductor behavior with significantly deep and broad minima around 100[Formula: see text] which becomes sharper for sample with higher Mn concentration.

APA, Harvard, Vancouver, ISO, and other styles

24

Yu, Shuang, Guoqiang Zhao, Yi Peng, Xiancheng Wang, Qingqing Liu, Runze Yu, Sijia Zhang, et al. "(Ba,K)(Zn,Mn)2Sb2: A New Type of Diluted Magnetic Semiconductor." Crystals 10, no. 8 (August 10, 2020): 690. http://dx.doi.org/10.3390/cryst10080690.

Full text

Abstract:

A series of polycrystalline samples of a new diluted magnetic semiconductor (DMS) (Ba,K)(Zn,Mn)2Sb2 has been synthesized and systematically studied. The parent phase is the so-called “Zintl compound” BaZn2Sb2, a week-degenerate semiconductor with a narrow band gap of 0.2 eV. In (Ba,K)(Zn,Mn)2Sb2, the charge is doped by (Ba,K) substitution while the spin is independently doped by (Zn,Mn) substitution. (Ba,K)(Zn,Mn)2Sb2 and analogue (Ba,K)(Zn,Mn)2As2 have comparable narrow band gaps, carrier and spin concentrations. However, the former establishes a short-range spin-glass order at a very low temperature (<10 K), while the latter forms a long-range ferromagnetic ordering with a Curie temperature up to 230 K. The sharp contrast makes (Ba,K)(Zn,Mn)2Sb2 to be a touchstone for DMS theoretical models.

APA, Harvard, Vancouver, ISO, and other styles

25

GRUBIN, H. L. "SPIN DEPENDENT WIGNER FUNCTION SIMULATIONS OF DILUTED MAGNETIC SEMICONDUCTOR SUPERLATTICES – B FIELD TUNING." International Journal of High Speed Electronics and Systems 17, no. 04 (December 2007): 877–88. http://dx.doi.org/10.1142/s0129156407005053.

Full text

Abstract:

Two terminal devices have traditionally provided band-structure based high frequency operation. Third terminal control often involves hybrid design approaches. The presence of diluted magnetic semiconductor layers in device fabrication should permit the magnetic field to function as a pseudothird terminal. This is discussed for single barrier, double barrier and superlattice structures, where control is demonstrated. The limits of high frequency operation are discussed in general terms with application to barrier devices and superlattices containing DMS layers.

APA, Harvard, Vancouver, ISO, and other styles

26

Foygel, M., and A. G. Petukhov. "ANISOTROPY OF THE BOUND MAGNETIC POLARON STATES AND COLOSSAL HOPPIG MAGNETORESISTANCE IN DILUTE MAGNETIC SEMICONDUCTORS." International Journal of Modern Physics B 15, no. 24n25 (October 10, 2001): 3228–37. http://dx.doi.org/10.1142/s0217979201007531.

Full text

Abstract:

A theory of positive and negative colossal magnetoresistance (CMR) in dilute magnetic semiconductors (DMS) is presented. The phenomenon is described in the framework of bound magnetic polaron (BMP) hopping, driven by thermodynamic fluctuations of the local magnetization. The latter is caused by fluctuating spins of the magnetic atoms which strongly interact with the spin of a trapped electron or a hole within the localization volume. The authors' previous approach to the BMP hopping problem1,2, based on the Ginzburg-Landau effective Hamiltonian method, has been generalized in order to take into account the anisotropy of the BMP states. This effect can be attributed to the anisotropy of the local exchange field and/or to the field-induced anisotropy of the magnetic susceptibility. In DMS the latter is shown to affect the position and the shape of the maximum in the magnetic-field dependence of CMR.

APA, Harvard, Vancouver, ISO, and other styles

27

Wu, Jian, H. R. Gutierrez, and P. C. Eklund. "Synthesis and Raman Scattering from Zn1−x MnxS Diluted Magnetic Semiconductor Nanowires." Journal of Nanoscience and Nanotechnology 8, no. 1 (January 1, 2008): 393–99. http://dx.doi.org/10.1166/jnn.2008.250.

Full text

Abstract:

The growth of Diluted Magnetic Semiconducting (DMS) Zn1−x MnxS (0 ≤ x < 0 6) nanowires (NWs) using a three-zone furnace and two solid sources is reported. The approach is generally applicable to many binary and ternary NW systems that grow by the Vapor-Liquid-Solid growth mechanism. Mn concentration was controlled by the temperature of the Mn source. The Zn/Mn ratio was found to determine the crystalline structure, i.e., wurtzite or zinc blende. High-resolution transmission electron microscopy measurements revealed highly crystalline single phase NWs. The vibrational properties of the DMS NWs with different Zn/Mn ratios were studied by correlating their Raman scattering spectra with the composition measured by Energy Dispersive X-Ray Spectroscopy (EDS). We find that the transverse optical (TO) phonon band disappears at the lowest Mn concentrations, while the longitudinal optical (LO) phonon band position was found insensitive to x. Three additional Raman bands were observed between the ZnS q = 0 TO and LO phonons when Mn atoms were present in the NWs. These bands are similar to those reported previously for bulk Zn1−x MnxS and their origin is still controversial.

APA, Harvard, Vancouver, ISO, and other styles

28

Declémy, Alain, Cyril Dupeyrat, Lionel Thomé, and Aurelien Debelle. "Microstructural Study of Fe-Implanted SiC: Comparison of Different Post-Implantation Treatments." Materials Science Forum 615-617 (March 2009): 461–64. http://dx.doi.org/10.4028/www.scientific.net/msf.615-617.461.

Full text

Abstract:

Silicon carbide (SiC) could be a good candidate for Diluted Magnetic Semiconductor (DMS). In this paper we report on preliminary results on the microstructure of Fe-implanted 6H-SiC subsequently submitted to Rapid Thermal Annealing (RTA), laser processing in the solid phase and swift heavy ion irradiation and analyzed by means of X-ray diffraction (XRD) and Rutherford backscattering and channeling (RBS/C).

APA, Harvard, Vancouver, ISO, and other styles

29

Grubin, H. L. "Transient Wigner Function Studies of DMS Barrier Devices." Advances in Science and Technology 52 (October 2006): 36–41. http://dx.doi.org/10.4028/www.scientific.net/ast.52.36.

Full text

Abstract:

Incorporating diluted magnetic semiconductor (DMS) layers within barrier devices offers new device design potential. To study these devices we have generalized an existing time dependent transient algorithm that couples the Wigner transport equation to Poisson’s equation and an external circuit. For electron transport we have studied alterations in the dc and time dependent behavior of resonant tunneling diodes with DMS barriers and wells, have transformed a single barrier structure into a double barrier structure and examined the increased functionality of the devices. We present new results, including some preliminary calculations incorporating holes, discuss transients and the potential role that DMS layers will play in controlling the transient operation of superlattice structures.

APA, Harvard, Vancouver, ISO, and other styles

30

Wang, Shiwei, Min Zhong, Cong Liu, Ying Li, Mingyuan Zhu, Hongming Jin, and Yemin Hu. "Effects of Temperature on the Microstructure and Magnetic Property of Cr-Doped ZnO DMS Prepared by Hydrothermal Route Assisted by Pulsed Magnetic Fields." Journal of Chemistry 2013 (2013): 1–7. http://dx.doi.org/10.1155/2013/830372.

Full text

Abstract:

In the present work, Cr-doped ZnO diluted magnetic semiconductor was synthesized by hydrothermal method under pulsed magnetic fields. The samples were characterized by XRD, SEM, VSM, Raman, and XPS techniques. Results demonstrated that Zn ions in the ZnO crystal lattice were partially displaced by Chromium (III) ions. All samples show room temperature ferromagnetism which was enhanced by pulsed magnetic fields. The mechanism of ferromagnetism of Cr-doped ZnO particles was discussed.

APA, Harvard, Vancouver, ISO, and other styles

31

Habib, Shaimaa A., Mona B. Mohamed, Samia A. Saafan, and Talaat M. Meaz. "Synthesis, characterization and promising properties of Fe3O4/CdSe nanocomposite." EPJ Web of Conferences 201 (2019): 02002. http://dx.doi.org/10.1051/epjconf/201920102002.

Full text

Abstract:

Nowadays there is a continuously increasing worldwide concern for the utilization of magnetic semiconductor nanocomposites. We synthesized bifunctional magnetic–luminescent nanocomposites with Fe3O4 nanoparticles as the cores and CdSe as the shells by a facile direct precipitation method. Transmission electron microscopy (TEM) images revealed that the obtained bifunctional nanocomposites had a core–shell structure, in a spherical shape with a particle radius of about 10.3nm, and the shell thickness of about 2.2nm. The flower shape is due to the inhomogeneous growth of CdSe due to the presence of many active sites which turn to be nucleation centers for the CdSe on the surface of the nano-magnetite. The X-ray diffraction (XRD) patterns showed a cubic spinel structure of the Fe3O4 core. Magnetic measurements indicated that the presence of CdSe in the composite reduces its magnetic properties. Optical measurements of the Fe3O4/CdSe nanocomposite show that the prepared samples have dual functions, optical tunable band gap of the semiconductor quantum dots and the magnetic properties of magnetite. This type of composites would be considered as dilute magnetic semiconductors (DMS).

APA, Harvard, Vancouver, ISO, and other styles

32

Rusu, Madalin Ion, Daniel Tenciu, Nicolae Catalin Zoita, Roger Notonier, Alain Tonetto, and Cristiana Eugenia Ana Grigorescu. "Preparation of Bulk Polycrystalline MnGe_xSb_y (x = 0.5-1.0; y = 1.5-2.2) Doped with Co or Fe." Applied Mechanics and Materials 760 (May 2015): 329–34. http://dx.doi.org/10.4028/www.scientific.net/amm.760.329.

Full text

Abstract:

Bulk polycrystalline MnGexSby materials doped with Co or Fe were prepared and investigated with the aim of obtaining new diluted magnetic semiconductor (DMS) materials. An innovative preparation method was also established. Investigation techniques like X-ray diffraction (XRD), Raman scattering, and scanning electron microscopy (SEM) associated with energy dispersive X-ray analysis (EDX) have been employed to derive the structural properties and the composition of the bulk material.

APA, Harvard, Vancouver, ISO, and other styles

33

TOROPOV, A. A., YA V. TERENT'EV, A. V. LEBEDEV, P. S. KOP'EV, S. V. IVANOV, T. KOYAMA, K. NISHIBAYASHI, A. MURAYAMA, and Y. OKA. "SPIN DYNAMICS IN III-V/II-VI: Mn HETEROVALENT QUANTUM WELLS." International Journal of Modern Physics B 23, no. 12n13 (May 20, 2009): 2739–49. http://dx.doi.org/10.1142/s0217979209062293.

Full text

Abstract:

We report on the spectroscopic magnetooptical studies of spin dynamics in diluted magnetic semiconductor (DMS) GaAs / AlGaAs / ZnSe / ZnCdMnSe heterovalent double quantum wells (QW). The transients of circularly polarized photoluminescence in an external magnetic field are detected in the structures with different widths of the GaAs QW. The analysis of the data, performed within the rate-equation model, has allowed separate estimations of the spin relaxation rate of localized electrons and holes. The spin flip of the electrons confined in the DMS ZnCdMnSe QW is faster than 20 ps, whereas the spin flip of the heavy hole localized in the GaAs QW is as long as ~9 ns. The long spin flip of the holes is presumably governed by their strong 3-dimensional localization.

APA, Harvard, Vancouver, ISO, and other styles

34

Babanlı, Arif M., Ekrem Artunç, and Turgut F. Kasalak. "Electron g-Factor in Diluted Magnetic Semiconductor Quantum Well with Parabolic Potential in the Presence of Rashba Effect and Magnetic Field." Zeitschrift für Naturforschung A 70, no. 2 (February 1, 2015): 109–14. http://dx.doi.org/10.1515/zna-2014-0254.

Full text

Abstract:

AbstractWe have studied the Rashba spin-orbital effect on a diluted magnetic semiconductor (DMS) quantum well with parabolic potential in the presence of a magnetic field parallel to the z axis, taking into account the Zeeman coupling and the s-d exchange interaction between the carriers and the magnetic ions. We have obtained an analytical expression for the electron energy spectrum, which depends on the magnetic ion concentration, temperature, and strength of magnetic field. By using the obtained energy spectrum, we calculated the electron effective g*-factor. We have found that effective g*-factor increases when the magnetic field increases; by increasing the strength of spin-orbit interaction, the electron g*-factor decreases and by increasing the temperature, the electron g*-factor increases.

APA, Harvard, Vancouver, ISO, and other styles

35

Park, K., L. Salamanca-Riba, and B. T. Jonker. "TEM studies of (ZnSe/FeSe) superlattices." Proceedings, annual meeting, Electron Microscopy Society of America 50, no. 2 (August 1992): 1382–83. http://dx.doi.org/10.1017/s0424820100131541.

Full text

Abstract:

Diluted magnetic semiconductors (DMS) are of considerable interest in the area of heterostructures and superlattices because the lattice parameter, energy gap, and effective mass can be “tuned” in a controlled fashion by varying the composition. This tunability has been exploited in the fabrication of DMS superlattices. Since the superlattices can be grown with a wide range of choices of materials, there is a great variety of possible applications requiring magneto-optical properties. However, the lattice mismatch between the constituent layers in the superlattice and between the superlattice and the substrate makes it difficult to grow high quality superlattices.Superlattices of (11.4 Å FeSe/34.0 Å ZnSe)12 (sample A) and (20.0 Å FeSe/45.3 Å ZnSe)6 (sample B) were grown on (001) GaAs substrates using MBE. Sample A was grown on a ZnSe buffer layer with a thickness of 500 Å on a (001) GaAs substrate, while sample B was grown directly on a GaAs substrate. TEM samples were prepared by mechanical grinding, dimple grinding, and ion-milling (3.0 keV Ar+ ions and 1 mA current) at liquid nitrogen temperature.

APA, Harvard, Vancouver, ISO, and other styles

36

Machado, Lucius Vinicius Rocha, L. F. Mouzinho, M. R. Silva, E. M. J. A. Pallone, and A. C. F. M. Costa. "Influence on Doping of 0.4 mol of Co in ZnO Aiming their Application in DMS." Materials Science Forum 820 (June 2015): 181–86. http://dx.doi.org/10.4028/www.scientific.net/msf.820.181.

Full text

Abstract:

This paper proposes evaluate the effect on doping of 0.4mol of Co in ZnO, Aiming to use in diluted magnetic semiconductor (DMSs), so for this purpose, an evaluation of the characteristics: structural, morphological and magnetic was investigated. The samples were synthesized by combustion reaction using urea as fuel and an electric heater as source of heating. During the synthesis was performed measurements of temperature and time of combustion flame. The samples were characterized by X-ray diffraction (DRX), adsorption of nitrogen (BET), scanning electron microscopy (SEM), particle size distribution and magnetic measurement. The maximum temperature, and reaction time were, 520 oC and 240 s. The data of the XRD showed how phase majority the ZnO, with crystallite size of 27 nm and trace of second phase CoCo2O4. Presented superficial area of 33.5 m2/g, with morphology consisting of agglomerates in the form of balls smaller than 5 μm. The sample presented behavior ferrimagnetic with saturation magnetization of 0.32 emu/g, type of a magnetic semiconductor.

APA, Harvard, Vancouver, ISO, and other styles

37

Pong, W. F., R. A. Mayanovic, K. T. Wu, P. K. Tseng, B. A. Bunker, A. Hiraya, and M. Watanabe. "X-ray Absorption Near Edge Structure (XANES) Studies of Diluted Magnetic Semiconductors (DMS) Zn1-xYxS (Y=Mn, Fe, Co) Systems." Japanese Journal of Applied Physics 32, S2 (January 1, 1993): 722. http://dx.doi.org/10.7567/jjaps.32s2.722.

Full text

APA, Harvard, Vancouver, ISO, and other styles

38

Thirupathi, C., S. Nithiyanantham, M. Sentilkumar, A. Arivudainambi, S. Mahalakshmi, and B. Natarajan. "Synthesis and Characterization of Co-Doped ZnO Diluted Magnetic Semiconductor for Spintronics Application." Advanced Science, Engineering and Medicine 12, no. 4 (April 1, 2020): 524–29. http://dx.doi.org/10.1166/asem.2020.2554.

Full text

Abstract:

The diluted magnetic semiconductor (DMS), are promising materials in the ferromagnetic exchange coupling between localized spins. ZnO nanoparticles in pure and cobalt doped with 2%, 4%, 6% and 8% were prepared through co-precipitation method at room temperature. XRD analysis showed the Co doped ZnO crystalizes in a wurzite structure. The particle size decreases with increase in concentration of cobalt. The SEM micrographs shows similar and regular equal in size depends with the increase of Co concentration and formation of spherical super structure and confirmed the Co2+ is completely replaced into the Zn2+ site of ZnO host structure. The size depends with the concentration are evident from EDAX analysis. The remarkable spin performances with increase of Co are confirming the above results.

APA, Harvard, Vancouver, ISO, and other styles

39

Jian, Wen-Bin, I.-Jan Chen, Tai-Ching Liao, Yi-Ching Ou, Cheng-Hsun Nien, Zhong-Yi Wu, Fu-Rong Chen, Ji-Jung Kai, and Juhn-Jong Lin. "Size Dependent Magnetization and High-Vacuum Annealing Enhanced Ferromagnetism in Zn1−xCoxO Nanowires." Journal of Nanoscience and Nanotechnology 8, no. 1 (January 1, 2008): 202–11. http://dx.doi.org/10.1166/jnn.2008.n13.

Full text

Abstract:

Diameter controllable ZnO nanowires have been fabricated by thermal evaporation (vapor transport) with various sizes of gold nanoparticles as catalysts. Diluted magnetic semiconductor (DMS) Zn1−xCoxO nanowires were then made by high energy Co ion implantation. The as-implanted and the argon-annealed Zn1−xCoxO nanowires displayed weak ferromagnetism while the high-vacuum annealed nanowires exhibited strong ferromagnetic ordering at room temperature. Size dependent behavior has been observed in the magnetic field and temperature dependences of magnetization. The shrinkage of the nanowire diameter reduced the spontaneous magnetization as well as the hysteresis loops. Field cooled and zero-field cooled magnetization and coercivity measurements were performed between 2 and 300 K to study the evolution of magnetism from the weak to the strong ferromagnetic states. In particular, superparamagnetic features were observed and shown to be intrinsic characteristics of the DMS Zn1−xCoxO nanowires. The room-temperature spontaneous magnetization of individual Zn1−xCoxO nanowires was also established by using magnetic force microscope measurements.

APA, Harvard, Vancouver, ISO, and other styles

40

Machado, Lucius Vinicius Rocha, Diogenes M. P. Souza, Nilman D. S. Gomes, Manoel Ribeiro da Silva, Lucilene F. Mouzinho, and Ana Cristina Figueredo Melo Costa. "Synthesis by Combustion Reaction of the System Zn₀_,₆Fe₀_,₄O for Application as DMS: Avaliation of the Type of Container." Materials Science Forum 798-799 (June 2014): 396–401. http://dx.doi.org/10.4028/www.scientific.net/msf.798-799.396.

Full text

Abstract:

This paper proposes to investigate the influence of the type of container on the structure, morphology and measures magnetic nanoparticles of the Zn0.6Fe0.4O synthesized by combustion reaction, for use as diluted magnetic semiconductors (DMSs). For synthesis were used as containers stainless crucibles and porcelain. The heating was realized in a muffle furnace at 500 °C. During the reactions, were performed measurements of the maximum temperature and total time of combustion reaction. The synthesized samples were characterized by XRD, SEM and magnetic measurements. The maximum temperatures obtained were 478 and 456 °C and total reaction time of 285 and 195 s for the samples synthesized in the crucible of stainless steel and porcelain, respectively. In both containers were possible to obtain single phase material with average crystallite size of 26 to 37 nm, irregular agglomerates formed by, behavior ferrimagnetic whose, saturation magnetization values of 1.6 e 2.0 emu/g respectively.

APA, Harvard, Vancouver, ISO, and other styles

41

Torquato, R., E. Shirsath Sagar, Ruth Herta Goldsmith Aliaga Kiminami, and Ana Cristina Figueiredo de Melo Costa. "Structural Characterization, and Magnetic Morphological Study of Ni⁺² Doped ZnO Synthesized by Combustion Reaction Application for DMS." Materials Science Forum 727-728 (August 2012): 511–15. http://dx.doi.org/10.4028/www.scientific.net/msf.727-728.511.

Full text

Abstract:

ZnO is a semiconductor that can be doped with transition metal ions, and thus becomes feasible to use in the diluted magnetic semiconductor (DMS), or semiconductor with magnetic properties. In this work we have studied the influence of doping of Ni+2on the structural, morphological and magnetic properties of Zn1-xNixO system, to x = 0.07, 0.1 and 0.2 mol of Ni+2synthesized by combustion reaction. The systems were characterized by XRD, SEM and VSM. The maximum temperatures ranged from 639 K and 683 K. All systems showed a majority phase formation of ZnO, with the presence of the second phase NiO. The crystallite size for the majority phase varied between 49 and 56nm. All systems have resulted in samples with a morphology consisting of dense clusters, formed by particles pre-sintered and shaped roughly hexagonal plates. The magnetic measurements showed that the values of saturation magnetization lies between 4.6 to 28.5emu/g, remanent magnetization of 0.01 to 0.3 emu/g, coercive force values varies between 12.7 and 62.4 Oe and Curie temperature ranging from 308 to 311K.

APA, Harvard, Vancouver, ISO, and other styles

42

Li, Chun-Lei, Yan Xu, and Yong Guo. "Photon-Assisted Spin-Dependent Tunneling in a Magnetic-Field Tunable Diluted Magnetic Semiconductor Structure with a Nonmagnetic Barrier." SPIN 08, no. 01 (March 2018): 1840007. http://dx.doi.org/10.1142/s2010324718400076.

Full text

Abstract:

Using the Floquet theory and effective-mass approximation theory, we have investigated the terahertz (THz) photon-assisted transport through a magnetic-field tunable diluted magnetic semiconductor (DMS) structure with a nonmagnetic barrier under multi-physical fields, including an external magnetic field, an electric field and a THz field. It is found that a THz field and an electric field can greatly affect the transmission coefficient and current density as well as the corresponding polarizations. As a result, some asymmetric ‘Fano’ type transmission resonance appear at some specific energy. With the applied bias increasing, some quasi platforms of the polarization began to take shape. Furthermore, the transmission coefficient suppression or augmentation can be clearly seen from the variation tendency of current density. It is noteworthy that the amplitude of current–density polarization becomes larger under a THz field and a small magnetic field. These remarkable properties of spin polarization might be beneficial to the design of spin filtering devices.

APA, Harvard, Vancouver, ISO, and other styles

43

Shah, A., Jamil Ahmad, Ishaq Ahmad, Mazhar Mehmood, Arshad Mahmood, and Muhammad Asim Rasheed. "Copper ion implanted aluminum nitride dilute magnetic semiconductors (DMS) prepared by molecular beam epitaxy." Applied Surface Science 317 (October 2014): 262–68. http://dx.doi.org/10.1016/j.apsusc.2014.08.112.

Full text

APA, Harvard, Vancouver, ISO, and other styles

44

Ziat, Younes, Maryama Hammi, Zakaryaa Zarhri, Charaf Laghlimi, Rachid Bouachraoui, Omar El Rhazouani, and Julio Cesar Cruz Argüello. "Investigation on Mo-doped SnO2 for potential use in magnetoelectronic applications: The DFT framework." International Journal of Modern Physics B 34, no. 05 (February 17, 2020): 2050020. http://dx.doi.org/10.1142/s0217979220500204.

Full text

Abstract:

The goal of this paper is to study the effect of the small amount of molybdenum-doped [Formula: see text] on the magnetism behavior of that system. We utilized the density functional theory (DFT): DFT framework within MACHIKANEYAMA2002V09 package based on Coherent Potential Approximation (CPA). Inducing the magnetism in the diluted magnetic semiconductors (DMS) with a low dopant concentration at adequate room-temperature is a challenge, so, we restricted the Mo impurity at 2%. In addition, the small amount of Mo-doped [Formula: see text] is found optimal in many studies related to other fields. The ferromagnetic stability is observed in [Formula: see text] system, since the [Formula: see text] state of Mo element is found around the Fermi level and is 100% spin polarized, the half-metallic characteristic is useful in magnetoelectronic applications. Within the mean-field approximation (MFA) we predict the Curie temperature, as an obtained value, the [Formula: see text] K, consequently, the present system showed potential promise for real applications.

APA, Harvard, Vancouver, ISO, and other styles

45

Liu, Jia Jia, Tian Min Lei, Yu Ming Zhang, Pei Ting Ma, and Zhi Yong Zhang. "First-Principle Calculations for Magnetism of Mn-Doped Graphene." Advanced Materials Research 709 (June 2013): 184–87. http://dx.doi.org/10.4028/www.scientific.net/amr.709.184.

Full text

Abstract:

Mn doped graphene-based dilute magnetic semiconductors (DMS) are investigated using the first-principle calculation based on density functional theory. In this paper, the Mn-C bond length, formation energy and magnetic moment are calculated in different doping systems and their density of states is made a detailed analysis. It is found that Mn-doped graphene has strong ferromagnetic properties and the magnetic moments of graphene supercells are different with the impurity concentrations. These supercells of a Mn atom substituting a C atom are increasingly stable with extending cells and the 11×11 supercell possesses the biggest magnetic moment of 3.8μB in these systems. The analysis of the density of states indicates the magnetic properties of Mn-doped graphene derive from the p-d exchange mechanism.

APA, Harvard, Vancouver, ISO, and other styles

46

Kervan, Selçuk, and Nazmiye Kervan. "First-principles study on half-metallic ferromagnetism in the diluted magnetic semiconductor (DMS) Al1−xMnxP compounds." Journal of Magnetism and Magnetic Materials 382 (May 2015): 63–70. http://dx.doi.org/10.1016/j.jmmm.2015.01.054.

Full text

APA, Harvard, Vancouver, ISO, and other styles

47

Abdullahi, Sabiu Said, Garba Shehu Musa Galadanci, Norlaily Mohd Saiden, and Josephine Ying Chyi Liew. "Assessment of Magnetic Properties between Fe and Ni Doped ZnO Nanoparticles Synthesized by Microwave Assisted Synthesis Method." Solid State Phenomena 317 (May 2021): 119–24. http://dx.doi.org/10.4028/www.scientific.net/ssp.317.119.

Full text

Abstract:

The emergence of Dilute Magnetic Semiconductors (DMS) with a potentials for spintronic application have attracted much researches attention, special consideration has been given to ZnO semiconductor material due to its wide band gap of 3.37 eV, large exciting binding energy of 60 meV, moreover, its ferromagnetic behavior at room temperature when doped with transition metals. MxZn1-xO (M = Fe or Ni) nanoparticles were synthesized by microwave assisted synthesis method calcined at 600°C. The structural, morphological and magnetic properties of these nanoparticles were studied using X-ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM) and Vibrating Sample Magnetometer (VSM) respectively. Single phase Wurtzite hexagonal crystal structure was observed for the undoped and Fe doped ZnO nanoparticles with no any impurity, whereas Ni doped ZnO nanoparticles shows the formation of NiO impurities. The magnetic measurement reveals a diamagnetic behavior for the undoped ZnO meanwhile a clear room temperature ferromagnetism was observed for both Fe and Ni doped ZnO. Fe doped ZnO present a high saturation magnetization compared to Ni doped ZnO. However, Ni doped ZnO present high coercivity. The research was confirmed that Fe doped ZnO material will be good material combination for spintronic applications.

APA, Harvard, Vancouver, ISO, and other styles

48

Mekonnen Hailemariam, Sintayehu. "Electronic Structure and Room Temperature of 2D Dilute Magnetic Semiconductors in Bilayer MoS2-Doped Mn." Advances in Condensed Matter Physics 2020 (January 20, 2020): 1–8. http://dx.doi.org/10.1155/2020/9635917.

Full text

Abstract:

The electronic structure and magnetic properties of manganese- (Mn-) doped bilayer (BL) molybdenum disulfide (MoS2) are studied using the density function theory (DFT) plus on-site Hubbard potential correction (U). The results show that the substitution of Mn at the Mo sites of BL MoS2 is energetically favorable under sulfur- (S-) rich regime than Mo. The magnetic interaction between the two manganese (Mn) atoms in BL MoS2 is always ferromagnetic (FM) irrespective of the spatial distance between them, but the strength of ferromagnetic interaction decays with atomic distance. It is also found that two dopants in different layers of BL MoS2 communicate ferromagnetically. In addition to this, the detail investigation of BL MoS2 and its counterpart of monolayer indicates that interlayer interaction in BL MoS2 affects the magnetic interaction in Mn-doped BL MoS2. The calculated Curie temperature is 324, 418, and 381 K for impurity concentration of 4%, 6.25%, and 11.11%, respectively, which is greater than room temperature, and the good dilute limit of dopant concentration is 0–6.25%. Based on the finding, it is proposed that Mn-doped BL MoS2 are promising candidates for two-dimensional (2D) dilute magnetic semiconductor (DMS) for high-temperature spintronics applications.

APA, Harvard, Vancouver, ISO, and other styles

49

Sun, Y., F. V. Kyrychenko, G. D. Sanders, C. J. Stanton, G. A. Khodaparast, J. Kono, Y. H. Matsuda, and H. Munekata. "Probe of the Band Structure of MBE Grown p-Type InMnAs at Ultrahigh Magnetic Fields." SPIN 05, no. 01 (March 2015): 1550002. http://dx.doi.org/10.1142/s2010324715500022.

Full text

Abstract:

We present a theoretical and experimental study on electronic and magneto-optical properties of p-type paramagnetic InMnAs dilute magnetic semiconductor (DMS) alloys in ultrahigh (> 100 T) external magnetic fields (B). Theoretical calculations are based on an 8-band Pidgeon–Brown model which is generalized to include the wavevector dependence of the electronic states along B as well as s–d and p–d exchange interactions with localized Mn d-electrons. The spin-dependent electronic structure as a function of Mn doping is computed and the dependence of the valence band structure on parameters such as the sp–d exchange interaction strength and effective masses in paramagnetic p- InMnAs alloys are examined. The cyclotron resonance (CR) and magneto-optical properties of InMnAs are calculated using Fermi's golden rule. Two strong CR peaks are observed in p-type InMnAs alloys which correspond to the transitions within either heavy-hole (HH) or light-hole (LH) Landau levels. Furthermore, we also observed strong resonance absorption for electron-active polarization which can occur in p-type semiconductors originating from transitions between the light and heavy hole Landau levels.

APA, Harvard, Vancouver, ISO, and other styles

50

AMENTE, CHERNET, and P. SINGH. "EFFECTS OF PHOTO-EXCITATION AND MAGNON SCATTERING ON FERROMAGNETIC TRANSITION TEMPERATURE OF THE DILUTED MAGNETIC SEMICONDUCTOR (Ga1 - x, Mnx)As." Modern Physics Letters B 25, no. 04 (February 10, 2011): 273–80. http://dx.doi.org/10.1142/s0217984911025699.

Full text

Abstract:

Effects of photo-excitation and spin-wave scattering on magnetization of the diluted magnetic semiconductor (DMS) ( Ga , Mn ) As are theoretically studied. Green function formalism is used to find expression for magnetization and ferromagnetic transition temperature TC starting with a model Hamiltonian consisting of magnons, photons and an interaction of magnons with photons. According to our calculation, there is TC in the absence of magnetic impurity, x = 0, indicating that there could be electronically unpaired influential carriers/holes induced by photon irradiation resulting in residual itinerant band magnetization which can be revealed by experiments. Unusual upturn in magnetization near 0 K temperature values for larger magnon–photon coupling constant is also indicated. Moreover, enhancement of magnetization is established with increase in impurity concentration and even further in the presence of photon–magnon coupling which however decreases due to spin-wave scattering. This leads to the conclusion that at lower temperatures photon irradiation and at higher temperatures spin-wave scattering could affect the system properties predominantly.

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'DMS [Diluted Magnetic Semiconductors]'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles