Relevant bibliographies by topics / Magnetic nanocrystals

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  2. Dissertations / Theses
  3. Books
  4. Book chapters
  5. Conference papers
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Academic literature on the topic 'Magnetic nanocrystals'

Author: Grafiati
Published: 4 June 2021
Last updated: 6 September 2023

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Journal articles on the topic "Magnetic nanocrystals"

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Wang, Li, Hong Fang Sun, Hui Hua Zhou, and Jing Zhu. "Self-Assembly Growth and Size Control of Silver Nanocrystals for Nonvolatile Memory Applications." Materials Science Forum 610-613 (January 2009): 585–90. http://dx.doi.org/10.4028/www.scientific.net/msf.610-613.585.

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A film with a single-layer of size controlled silver nanocrystals embedded in silicon dioxide (SiO2) dielectric film by magnetic sputtering has been fabricated for nonvolatile memory applications. The effects of sputtering power, deposition time and substrate temperature on Ag nanocrystals formation were investigated. Transmission electron microscopy (TEM) images showed the as-prepared Ag nanocrystals had high uniformity in their size and distribution. The relationship between Ag nanocrystal size, density and electron storage capability as well as date retention time has been discussed.
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Zhang, Xinhai, Qiuling Chen, and Shouhua Zhang. "Ta2O5 Nanocrystals Strengthened Mechanical, Magnetic, and Radiation Shielding Properties of Heavy Metal Oxide Glass." Molecules 26, no. 15 (July 26, 2021): 4494. http://dx.doi.org/10.3390/molecules26154494.

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In this study, for the first time, diamagnetic 5d0 Ta5+ ions and Ta2O5 nanocrystals were utilized to enhance the structural, mechanical, magnetic, and radiation shielding of heavy metal oxide glasses. Transparent Ta2O5 nanocrystal-doped heavy metal oxide glasses were obtained, and the embedded Ta2O5 nanocrystals had sizes ranging from 20 to 30 nm. The structural analysis of the Ta2O5 nanocrystal displays the transformation from hexagonal to orthorhombic Ta2O5. Structures of doped glasses were studied through X-ray diffraction and infrared and Raman spectra, which reveal that Ta2O5 exists in highly doped glass as TaO6 octahedral units, acting as a network modifier. Ta5+ ions strengthened the network connectivity of 1–5% Ta2O5-doped glasses, but Ta5+ acted as a network modifier in a 10% doped sample and changed the frame coordination units of the glass. All Ta2O5-doped glasses exhibited improved Vicker’s hardness, magnetization (9.53 × 10−6 emu/mol), and radiation shielding behaviors (RPE% = 96–98.8%, MAC = 32.012 cm2/g, MFP = 5.02 cm, HVL = 0.0035–3.322 cm, and Zeff = 30.5) due to the increase in density and polarizability of the Ta2O5 nanocrystals.
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Yin, J. S., and Z. L. Wang. "Self-Assembled Cobalt Oxide Nanocrystals with Tetrahedral Shape." Microscopy and Microanalysis 4, S2 (July 1998): 736–37. http://dx.doi.org/10.1017/s1431927600023801.

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Nanocrystal materials are an emerging research field of chemistry, physics and materials science. The size and shape specificity of nanocrystals suggests them as building blocks for constructing selfassembly passivated nanocrystals superlattices (NCS's) or nanocrystals arrays (NCA) [1-6]. In this paper, NCAs of CoO with controlled tetrahedral shape are reported and their structural stability is examined by in-situ TEM.Cobalt oxide nanocrystals were synthesized by chemical decomposition of Co2(CO)8 in toluene under oxygen atmosphere, as given in detail elsewhere [1].Sodium bis(2-ethylhexyl) sulfosuccinate (Na(AOT)) was added as a surface active agent, forming an ordered monolayer passivation (called the thiolate) over the nanocrystal surface. The particle size was controlled by adjusting the wt.% ratio between the precursor and Na(AOT). The as-prepared solution contained Co, CoO and possibly C03O4 nanoparticles, and pure CoO nanoparticles were separated by applying a small magnetic field, which is generated by a horseshoe permanent magnet in vertical direction.
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Xiong, Zichang, Himashi P. Andaraarachchi, Jacob T. Held, Rick W. Dorn, Yong-Jin Jeong, Aaron Rossini, and Uwe R. Kortshagen. "Inductively Coupled Nonthermal Plasma Synthesis of Size-Controlled γ-Al2O3 Nanocrystals." Nanomaterials 13, no. 10 (May 12, 2023): 1627. http://dx.doi.org/10.3390/nano13101627.

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Gamma alumina (γ-Al2O3) is widely used as a catalyst and catalytic support due to its high specific surface area and porosity. However, synthesis of γ-Al2O3 nanocrystals is often a complicated process requiring high temperatures or additional post-synthetic steps. Here, we report a single-step synthesis of size-controlled and monodisperse, facetted γ-Al2O3 nanocrystals in an inductively coupled nonthermal plasma reactor using trimethylaluminum and oxygen as precursors. Under optimized conditions, we observed phase-pure, cuboctahedral γ-Al2O3 nanocrystals with defined surface facets. Nuclear magnetic resonance studies revealed that nanocrystal surfaces are populated with AlO6, AlO5 and AlO4 units with clusters of hydroxyl groups. Nanocrystal size tuning was achieved by varying the total reactor pressure yielding particles as small as 3.5 nm, below the predicted thermodynamic stability limit for γ-Al2O3.
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Kang, Myung Jong, Na Hyeon An, and Young Soo Kang. "Magnetic and Photochemical Properties of Cu Doped Hematite Nanocrystal." Materials Science Forum 893 (March 2017): 136–43. http://dx.doi.org/10.4028/www.scientific.net/msf.893.136.

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In this report, the magnetic and photochemical properties of Cu doped hematite nanocrystal was investigated intensively. The Cu doped hematite nanocrystals were prepared by hydrothermal method, changing the molar ratio of Cu precursors. The XRD and XPS techniques are used for revealing crystal and chemical state of Cu doped hematite nanocrystal. Raman spectroscopy was also used for confirming Cu atoms replacing Fe position in Cu doped hematite crystal. The UV-vis and UPS were used for assigning electronic band position for photocatalytic properties. Cu doped hematite showed the enhanced photocatalytic properties within photodegradation of methyl orange. Finally, by checking magnetic hysteresis loops of Cu doped hematites with VSM, it was revealed that the magnetic property of Cu doped hematite nanocrystal was increased after doping Cu into hematite nanocrystal, get the distortion of magnetic sub-lattices.
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Harfenist, S. A., Z. L. Wang, T. G. Schaaff, and R. L. Whettent. "A BCC Superlattice of Passivated Gold Nanocrystals." Microscopy and Microanalysis 4, S2 (July 1998): 716–17. http://dx.doi.org/10.1017/s1431927600023709.

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A recent development in the study of nanocrystalline materials has been the self-assembly of passivated nanometer scale building blocks into larger, well ordered structures reaching the micron scale. Nanocrystal supercrystals (NCS) have been observed in metallic, semiconductor, and magnetic materials. In most cases the nanocrystals (NXs) are encapsulated in some inert medium that effectively protects the nanocrystal core and its unique electronic and optical properties. Here we describe the self-assembly of gold nanocrystals (∼4.5 nm core diameter), passivated with hexanethiol self-assembled-monolayers into ordered regions exhibiting a body-centered-cubic (bcc) superstructure. Transmission Electron Microscopy (TEM) imaging and Electron Diffraction (ED) experiments were used to characterize the NCSs and their resulting superstructures.A large agglomeration of NCSs can be seen in figure 1. One can clearly see regions of periodicity within the nanocrystal aggregation.
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Zhan, Li, Qi Wei, Geng Yanxia, Xu Junzheng, and Wu Wangsuo. "Biodistribution of60Co–Co/Graphitic-Shell NanocrystalsIn Vivo." Journal of Nanomaterials 2011 (2011): 1–5. http://dx.doi.org/10.1155/2011/842613.

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The magnetic nano-materials, Co/graphitic carbon- (GC-) shell nanocrystals, were madeviachemicalvapour deposition (CVD) method, and their biodistribution and excretion in mice were studied by using postintravenously (i.v.) injecting with60Co–Co/GC nanocrystals. The results showed that about 5% of Co was embedded into graphitic carbon to form multilayer Co/GC nanocrystals and the size of the particle was ~20 nm, the thickness of the nanocrystal cover layer was ~4 nm, and the core size of Co was ~14 nm. Most of the nanocrystals were accumulated in lung, liver, and spleen after 6, 12, 18, and 24 h afteri.v.with60Co–Co/GC nanocrystals. The nanoparticles were cleared rapidly from blood and closed to lower level in 10 min after injection. The60Co–Co/GC nanocrystals were eliminated slowly from body in 24 h after injection, ~6.09% of60Co–Co/GC nanocrystals were excreted by urine, ~1.85% by feces in 24 h, and the total excretion was less than 10%.
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Lin, Fang Hsin, and Reuy An Doong. "Synthesis of Ferrite Nanoparticle and Ferrite-Gold Heterostructures." Advanced Materials Research 123-125 (August 2010): 251–55. http://dx.doi.org/10.4028/www.scientific.net/amr.123-125.251.

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The synthesis of uniform and monodispersed magnetic and optical nanocrystals has received much attention in recent years due to the size-dependent physicochemical properties. In this study, we have demonstrated a general approach for the synthesis of size-tunable ferrite and gold nanocrystals and their nanocomposite. The monodispersed magnetite nanocrystals were obtained by thermal decomposition of iron-oleate complex in a high boiling point solvent in presence of oleylamine and oleic acid. The size of magnetite nanocrystal can be tuned from 7 – 11nm by changing the amount of iron-oleate complex. The other key parameters such as temperature, amount of capping agents, types of solvent were also discussed. This synthetic procedure could also apply to synthesis other type of ferrite nanocrystals. When Mn-acetate was partially substituted for iron-oleate in a 1:2 ratio in the same reaction conditions as in the synthesis of Fe3O4, monodispersed MnFe2O4 nanocrytals with 14nm could be obtained. Except those magnetic nanocrystals, we also synthesized various sizes of monodispersed gold nanocrystals by reducing HAuCl4 in presence of t-butylamine-borane and oleylamine. By varying the reaction temperature, the particle size could be well-tuned from 2nm to 8nm with the characteristic surface plasmon absorption between 510 and 520 nm. For Fe3O4/Au composite, it was prepared via the decomposition of iron-oleate over the surface of the Au nanoparticles. The mean size of the Fe3O4/Au nanocomposite was ∼17 nm which shows a saturation magnetization of 46.92 emu/g and absorption peak at 512nm. These composites with both magnetic and optical properties would make them very promising in the fields of biomedine and environment.
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Posfai, M., and R. E. Dunin-Borkowski. "Magnetic Nanocrystals in Organisms." Elements 5, no. 4 (August 1, 2009): 235–40. http://dx.doi.org/10.2113/gselements.5.4.235.

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Kikkawa, Shinichi. "Nanocrystals of Nitrides and Oxides." Journal of Nano Research 24 (September 2013): 16–25. http://dx.doi.org/10.4028/www.scientific.net/jnanor.24.16.

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Nanocrystals are important to attain high performance in optical & magnetic materials such as phosphors, laser emitters and information recording media. They are also required in future devices that involve magnetoresistance, logic gates, magnetic resonance and metamaterials. Nanocrystals of oxides and nitrides (and oxynitrides) were studied as nanosized powders, nanowires and dispersed granular thin films. Recent advancements of such nanocrystals prepared at Hokkaido University are introduced in this paper. Nanocrystals were prepared in transparent conducting oxides, white LED phosphor oxides and oxynitrides and magnetic iron nitride. Nanowires were grown in semiconducting gallium oxynitride and magnetic nanogranular thin films were prepared both in oxide and nitride.
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Dissertations / Theses on the topic "Magnetic nanocrystals"

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Radovanovic, Pavle V. "Synthesis, spectroscopy, and magnetism of diluted magnetic semiconductor nanocrystals /." Thesis, Connect to this title online; UW restricted, 2004. http://hdl.handle.net/1773/8494.

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Shevchenko, Elena V. "Monodisperse magnetic alloy nanocrystals and their superstructures." [S.l. : s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=968507395.

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Norberg, Nicholas S. "Magnetic nanocrystals : synthesis and properties of diluted magnetic semiconductor quantum dots /." Thesis, Connect to this title online; UW restricted, 2006. http://hdl.handle.net/1773/8625.

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Simpson, Edward Thomas. "Electron holography of isolated and interacting magnetic nanocrystals." Thesis, University of Cambridge, 2009. https://www.repository.cam.ac.uk/handle/1810/252128.

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Mozul, K., A. Ishchenko, A. P. Kryshtal, L. P. Olkhovik, and Z. I. Sizova. "Magnetic Anisotropy of Ultra-small Nanocrystals of CoFe2O4." Thesis, Sumy State University, 2012. http://essuir.sumdu.edu.ua/handle/123456789/35365.

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Ferrimagnetic nanoparticles of CoFe2O4 with dimensions of 4-16 nm were synthesized by pyrolysis of a mixture of acetylacetonates of iron and cobalt. In the temperature range 300-500 K investigated field dependence of magnetization up o 18 kOe. Found a significant contribution of "surface" anisotropy to the effective anisotropy of the nanoparticles. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/35365
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Almeida, António José Sousa de. "Magnetic resonance studies of spin systems in semiconductor nanocrystals." Doctoral thesis, Universidade de Aveiro, 2016. http://hdl.handle.net/10773/18636.

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Doutoramento em Física
Esta tese apresenta um estudo experimental de sistemas de spins fornecidos por dopantes electrónicos e por defeitos capturadores de carga em nanocristais (NCs) semiconductores, por meio de técnicas de ressonância magnética. Aqui, investigámos problemas que têm efeitos limitadores de performance nas propriedades de NCs semiconductores para o seu uso em aplicações tecnológicas. Nomeadamente, estudámos a dopagem electrónica de NCs semiconductores. A dopagem é crítica para controlar o comportamento de semiconductores, que de outra forma seriam isoladores. Investigámos também defeitos capturadores de carga, que podem ter um impacto negativo na conductividade de NCs semiconductores ao capturar portadores de carga em estados electrónicos deslocalizados de NCs. Para além disso, abordámos a origem da anisotropia magnética em NCs de materiais diamagnéticos. Nesta tese, reportamos investigações usando medidas de ressonância paramagnética electrónica (RPE) quantitativa, dizendo respeito à eficiência de dopagem electrónica de Si NCs com átomos de P e à sua dependência com o ambiente envolvendo os NCs. Das medidas de RPE quantitativas, estimamos eficiências de dopagem nos NCs que são consistentes com a incorporação da maioria dos dopantes P como dadores substitucionais nos NCs. Observamos também que a eficiência de dopagem dos NCs varia em várias ordens de grandeza dependendo do ambiente envolvendo os NCs, devido a uma forte compensação dos dadores por moléculas absorbidas na superfície dos NCs. Usando espectroscopia RPE dependente da temperatura, mostramos também que a energia de ionização dos dopantes P em Si NCs aumenta relativamente ao seu correspondente cristal macroscópico devido a confinamento. Usamos espectroscopia RPE dependente da temperatura para estudar a interacção entre múltiplos dopantes incorporados num único Si NC e o seu impacto na estrutura electrónica destes NCs. Monitorizámos experimentalmente a interacção de troca em pares de dadores P (dímeros de dadores) em Si NCs através de um desvio da ressonância magnética do seu estado tripleto em relação ao paramagnetismo de Curie. Mostrámos que a interacção de troca entre dadores próximos entre si pode ser bem descrita pela teoria de massa efectiva, permitindo o cálculo de muitas configurações de dopantes e permitindo a consideração de efeitos estatísticos cruciais em conjuntos de nanocristais. Descobrimos que dímeros de dadores induzem estados discretos num NC, e que a sua separação energética difere em até três ordens de grandeza para dímeros colocados aleatoriamente num conjunto de NCs devido a uma enorme dependência da energia de troca na configuração do dímero. Investigámos também sistemas de spins induzidos por defeitos capturadores de carga e como estes defeitos podem afectar a dopagem de NCs. Identificamos a presença de dois estados de carga de um defeito em NCs de CdSe usando espectroscopia RPE combinada com a afinação electrónica de NCs através de dopagem com Ag induzida quimicamente. A partir de de RPE foto-induzido, mostramos que estes defeitos têm um papel central na fixação do nível de Fermi em conjuntos de NCs. Através da análise da dependência do sinal de RPE dos defeitos com a concentração de dopantes de Ag, mostramos também que os defeitos actuam como capturadores efectivos de electrões nos NCs. Do RPE dependente da temperatura, estimamos um limite inferior para a energia de ionização dos defeitos estudados. Com base nas características do espectro RPE dos defeitos observados, propomos que está associado a lacunas de Se com o estado paramagnético sendo o estado positivo do defeito. Para além disso, mostramos que as interacções magnéticas entre spins associados a defeitos nos NCs podem induzir efeitos de anisotropia magnética em conjuntos de NCs que não são esperados acontecer no cristal macroscópico correspondente. Usando espectroscopia de ressonância ferromagnética (RFM) com dependência angular, medimos a anisotropia magnética em conjuntos de aleatórios de NCs de CdSe através da gravação do espectro de ressonância magnética para várias orientações do campo magnético externo. As dependências angulares do campo ressonante são diferente para conjuntos aparentemente similares de NCs de CdSe. Mostramos que a forma e amplitude da variação angular do RFM pode ser bem descrita po um modelo simples que toma em consideração as interacções dipolo-dipolo entre dipolos localizados na superfície dos NCs. Os dipolos na superfície podem originar de ligações pendentes em sítios da superfície que não estão passivados por ligantes. Dos nossos cálculos, descobrimos que para diferentes conjuntos aleatórios de NCs a força da anisotropia magnética induzida por interacções dipolo-dipolo pode tomar valores abrangendo quatro ordens de grandeza, dependendo do arranjo específico dos NCs no conjunto e da distribuição específica dos dipolos na superfície de cada NC. Esta enorme variabilidade pode justificar a disparidade de anisotropias magnéticas observada nas nossas experiências.
This thesis presents an experimental study of systems of spins provided by electronic dopants and by charge trapping defects in semiconductor NCs, by means of magnetic resonance spectroscopy techniques. Here, we have investigated issues that have performance-limiting effects on the properties of semiconductor NCs for their use in technological applications. Namely, we have studied the electronic doping of semiconductor NCs. Doping is critical to control the behavior of semiconductors, which would otherwise be electrically insulating. We have further investigated charge trapping defects in semiconductor NCs, which can have a negative impact on the conductivity of semiconductor NCs by capturing charge carriers from delocalized electronic states of the NCs. Moreover, we addressed the origin of magnetic anisotropy in NCs of diamagnetic materials. In this thesis, we report investigations using quantitative electron paramagnetic resonance (EPR) measurements concerning the efficiency of electronic doping of Si NCs with P atoms and its dependence on the environment surrounding the NCs. From quantitative EPR measurements, we estimate doping efficiencies in the NCs that are consistent with the incorporation of most P dopants as substitutional donors in the NCs. We further observe that the doping efficiency of the NCs varies by several orders of magnitude depending on the NCs surrounding environment due to a strong compensation of donors by molecules adsorbed to the NCs surface. Using temperature-dependent EPR spectroscopy, we further show that the ionization energy of P dopants in Si NCs increases with respect to their bulk counterpart due to confinement. We use temperature-dependent EPR spectroscopy to study the interaction between multiple P dopants incorporated in a single Si NC and its impact on the electronic structure of these NCs. We experimentally probe the exchange interaction in pairs of P donors (donor dimers) in Si NCs via a deviation of their triplet-state magnetic resonance from Curie paramagnetism. We showed that the exchange coupling of closely spaced donors can be well described by effective mass theory, enabling the calculation of many dopant configurations and allowing the consideration of statistical effects crucial in NC ensembles. We find that donor dimers induce discrete states in a NC, and that their energy splitting differs by up to three orders of magnitude for randomly placed dimers in a NC ensemble due to an enormous dependence of the exchange energy on the dimer configuration. We also investigate systems of spins induced by charge trapping defects and how these defects can affect the doping of NCs. We identify the presence of two charge states of a defect in CdSe NCs using EPR spectroscopy, combined with electronic tuning of NCs via chemically induced Ag doping. From light-induced EPR, we show that these defects have a central role on Fermi level pinning of NC ensembles. By analyzing the dependence of the EPR signal of the defects on the concentration of Ag dopants, we further demonstrate that the defects act as effective electron traps in the NCs. From temperaturedependent EPR, we estimate a lower limit for the ionization energy of the studied defects. Based on the characteristics of the EPR spectrum of the observed defect, we propose that it is associated to Se vacancies with the paramagnetic state being the positively charged state of the defect. Moreover, we show that magnetic interactions between spins associated to defects in NCs can induce magnetic anisotropy effects in NCs ensembles that are not expected to occur in their bulk counterpart. Using angulardependent ferromagnetic resonance (FMR) spectroscopy, we measure the magnetic anisotropy in different random ensembles of CdSe NCs by recording magnetic resonance spectra for various orientations of the external magnetic field. The observed angular dependencies of resonant field are different for apparently similar CdSe NC ensembles. We show that the shape and amplitude of the FMR angular variation can be well described by a simple model that considers magnetic dipole-dipole interactions between dipoles located at the NCs surface. The surface dipoles may originate from dangling bonds on surface sites that are not passivated by ligands. From our calculations, we find that for different random ensembles of NCs the strength of the magnetic anisotropy induced by dipole-dipole interactions may take values spanning four orders of magnitude, depending on the specific arrangement of the NCs in the ensemble and the specific distribution of the surface dipoles in each NC. This huge variability may justify the disparity of magnetic anisotropies observed in our experiments.
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Larsen, Brian A. "Bioengineered iron-oxide nanocrystals: Applications in magnetic resonance imaging." Connect to online resource, 2008. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3337119.

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Tracy, Nicholas Alan. "Synthesis and Characterization of Magnetic II-VI Nanoparticles." Thesis, Virginia Tech, 2006. http://hdl.handle.net/10919/32507.

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Magnetic semiconductor nanocrystals are being studied for their potential application in the field of spintronics as spin-injectors for spin-based transistors and spin-based storage elements for nonvolatile memories. They also have a number of biomedical engineering applications including contrast enhancing agents for magnetic resonance imaging (MRI). In this study, we present a synthesis route to grow colloidal II-VI magnetic nanoparticles at room temperature with easily handled, relatively non-toxic source materials. CoSe and CrSe nanocrystals were synthesized in an aqueous solution where gelatin is used to retard the reaction. Characterization of the nanocrystals was done through transmission electron microscope (TEM) imaging and UV-Vis absorption spectroscopy. Spin-carrier relaxation times were determined using a superconducting quantum interference device (SQUID) magnetometer.
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Kumar, Kritika. "Microfluidic synthesis of superparamagnetic iron oxide nanocrystals for magnetic resonance imaging." Thesis, Imperial College London, 2013. http://hdl.handle.net/10044/1/18809.

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Superparamagnetic iron oxide nanoparticles (SPIONs) are of significant interest in areas such as drug delivery, hyperthermic treatment, magnetic resonance imaging (MRI) and selective separation of biological fluids. For all these applications there is a recognised need for improved synthetic methods that are capable of yielding SPIONs of uniform size, geometry and stoichiometry. Microfluidic reactors offer an attractive route to nanoparticle synthesis due to the superior control they provide over reaction conditions and particle properties relative to traditional bulk methods. In 2002 Edel et al.1 proposed the use of microfluidic reactors for nanoparticle synthesis due to the high levels of control they provide over key reaction parameters such as temperature, reagent concentrations and reaction time. Since that report a diversity of metal, metal oxide, compound semiconductor and organic nanomaterials have been successfully synthesised in microfluidic systems. Most reports of nanoparticle synthesis in microreactors have involved single-phase mode of operation, in which continuous streams of miscible fluids are manoeuvred through microscale channels where nucleation and growth take place. Such reactors, however, are poorly suited to the synthesis of SPIONs due to their high susceptibility to fouling. An alternative approach is to use droplet-based reactors in which an immiscible liquid is injected alongside the reaction mixture, causing the latter to spontaneously divide into a series of near identical droplets. In this thesis microfluidic synthesis of SPIONs in a controlled and reproducible manner is described. This work is focussed on improving the microfluidic methods for controlled synthesis of SPIONs and utilise the produced nanoparticles directly as contrast enhancers in MR imaging. The droplet based reactions were initially performed on polydimethylsiloxane (PDMS) microfluidic devices, however on such devices, low throughput was obtained. To overcome fabrication difficulty and to increase throughput, droplet-based synthesis was performed on the capillary-based reactor.
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Song, Qing. "Size and Shape Controlled Synthesis and Superparamagnetic Properties of Spinel Ferrites Nanocrystals." Diss., Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/7645.

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Size and Shape Controlled Synthesis and Superparamagnetic Properties of Spinel Ferrites Nanocrystals Qing Song 216 pages Directed by Dr. Z. John Zhang The correlationship between magnetic properties and magnetic couplings is established through the investigations of various cubic spinel ferrite nanocrystals. The results of this thesis contribute to the knowledge of size and shape controlled synthesis of various spinel ferrites and core shell architectured nanocrystals as well as the nanomagnetism in spinel ferrites by systematically investigating the effects of spin orbital coupling, magnetocrystalline anisotropy, exchange coupling, shape and surface anisotropy upon superparamagnetic properties of spinel ferrite nanocrystals. A general synthetic method is developed for size and shape control of metal oxide nanocrystals. The size and shape dependent superparamagnetic properties are discussed. The relationship between spin orbital coupling and magnetocrystalline anisotropy is studied comparatively on variable sizes of spherical CoFe2O4 and Fe3O4 nanocrystals. It also addresses the effect of exchange coupling between magnetic hard phase and soft phase upon magnetic properties in core shell structured spinel ferrite nanocrystals. The role of anisotropic shapes of nanocrystals upon self assembled orientation ordered superstructures are investigated. The effect of thermal stability of molecular precursors upon size controlled synthesis of MnFe2O4 nanocrystals and the size dependent superparamagnetic properties are described.
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Books on the topic "Magnetic nanocrystals"

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Iwasaki, Tomohiro, and Tomohiro Iwasaki. Organic solvent-free synthesis of magnetic nanocrystals with controlled particle sizes. Hauppauge, N.Y: Nova Science Publishers, 2010.

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Iwasaki, Tomohiro. Organic solvent-free synthesis of magnetic nanocrystals with controlled particle sizes. Hauppauge, N.Y: Nova Science Publishers, 2010.

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Zbroszczyk, Józef. Amorficzne i nanokrystaliczne stopy żelaza. Częstochowa: Wydawn. Politechniki Częstochowskiej, 2007.

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Pawlik, Piotr. Rola składu chemicznego i procesu wytwarzania w kształtowaniu właściwości magnetycznych masywnych amorficznych i nanokrystalicznych stopów żelaza. Częstochowa: Wydawn. Wydz. Inżynierii Procesowej, Materiałowej i Fizyki Stosowanej Politechniki Częstochowskiej, 2011.

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1962-, Zhukova Valentina, ed. Magnetic properties and applications of ferromagnetic microwires with amorpheous and nanocrystalline structure. Hauppauge, NY: Nova Science Publishers, 2009.

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van Schooten, Kipp. Optically Active Charge Traps and Chemical Defects in Semiconducting Nanocrystals Probed by Pulsed Optically Detected Magnetic Resonance. Heidelberg: Springer International Publishing, 2013. http://dx.doi.org/10.1007/978-3-319-00590-4.

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B, Cantor, ed. Novel nanocrystalline alloys and magnetic nanomaterials: An Oxford-Kobe materials text. Bristol: Institute of Physics Pub., 2005.

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1945-, Švec Petr, Idzikowski Bogdan, Miglierini Marcel, and North Atlantic Treaty Organization. Scientific Affairs Division., eds. Properties and applications of nanocrystalline alloys from amorphous precursors. Dordrecht: Kluwer Academic Publishers, 2005.

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Dantas, Noelio Oliveira. Diluted Magnetic Semiconductor Nanocrystals in Glass Matrix. INTECH Open Access Publisher, 2010.

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K, Rajendran, and Veeramanikandasamy T. Structural, Optical, Electrical and Magnetic Properties of Synthesized Manganese Sulfide Nanocrystals: A Study on the Influence of Process Parameters on Synthesis of MnS Nanocrystals. Independently Published, 2019.

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Book chapters on the topic "Magnetic nanocrystals"

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Petit, Christophe, Laurence Motte, Anh-Tu Ngo, Isabelle Lisiecki, and Marie-Paule Pileni. "Collective Magnetic Properties of Organizations of Magnetic Nanocrystals." In Nanocrystals Forming Mesoscopic Structures, 251–78. Weinheim, FRG: Wiley-VCH Verlag GmbH & Co. KGaA, 2006. http://dx.doi.org/10.1002/3527607587.ch10.

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Cozzoli, P. Davide, Concetta Nobile, Riccardo Scarfiello, Angela Fiore, and Luigi Carbone. "Magnetic Multicomponent Heterostructured Nanocrystals." In Magnetic Nanomaterials - Fundamentals, Synthesis and Applications, 217–90. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2017. http://dx.doi.org/10.1002/9783527803255.ch8.

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Wang, Zhong L., Yong Ding, and Jing Li. "Structures of Magnetic Nanoparticles and Their Self-Assembly." In Nanocrystals Forming Mesoscopic Structures, 49–74. Weinheim, FRG: Wiley-VCH Verlag GmbH & Co. KGaA, 2006. http://dx.doi.org/10.1002/3527607587.ch2.

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Kumar, J., S. Ramasubramanian, R. Thangavel, and M. Rajagopalan. "On the Optical and Magnetic Properties of Doped-ZnO." In ZnO Nanocrystals and Allied Materials, 309–29. New Delhi: Springer India, 2013. http://dx.doi.org/10.1007/978-81-322-1160-0_15.

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Richardi, Johannes, and Marie-Paule Pileni. "Self-Organization of Magnetic Nanocrystals at the Mesoscopic Scale: Example of Liquid-Gas Transitions." In Nanocrystals Forming Mesoscopic Structures, 75–89. Weinheim, FRG: Wiley-VCH Verlag GmbH & Co. KGaA, 2006. http://dx.doi.org/10.1002/3527607587.ch3.

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Marchessault, Robert H., Glen Bremner, and Grégory Chauve. "Fishing for Proteins with Magnetic Cellulosic Nanocrystals." In ACS Symposium Series, 3–17. Washington, DC: American Chemical Society, 2006. http://dx.doi.org/10.1021/bk-2006-0934.ch001.

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Giannelis, E. P., V. Mehrotra, J. K. Vassiliou, R. D. Shull, R. D. MacMichael, and R. F. Ziolo. "Magnetic and Optical Properties of γ-Fe2O3 Nanocrystals." In Nanophase Materials, 617–24. Dordrecht: Springer Netherlands, 1994. http://dx.doi.org/10.1007/978-94-011-1076-1_63.

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Liu, Xian Ming, and Shao Yun Fu. "Synthesis and Magnetic Properties of Spherical NiO Nanocrystals." In Solid State Phenomena, 1437–42. Stafa: Trans Tech Publications Ltd., 2007. http://dx.doi.org/10.4028/3-908451-30-2.1437.

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Morgenstern, Markus, Jens Wiebe, Felix Marczinowski, and Roland Wiesendanger. "Scanning Tunneling Spectroscopy on III–V Materials: Effects of Dimensionality, Magnetic Field, and Magnetic Impurities." In Quantum Materials, Lateral Semiconductor Nanostructures, Hybrid Systems and Nanocrystals, 217–43. Berlin, Heidelberg: Springer Berlin Heidelberg, 2010. http://dx.doi.org/10.1007/978-3-642-10553-1_9.

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Jayakumar, O. D., C. Persson, A. K. Tyagi, and C. Sudakar. "Experimental and Theoretical Investigations of Dopant, Defect, and Morphology Control on the Magnetic and Optical Properties of Transition Metal Doped ZnO Nanoparticles." In ZnO Nanocrystals and Allied Materials, 341–70. New Delhi: Springer India, 2013. http://dx.doi.org/10.1007/978-81-322-1160-0_17.

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Conference papers on the topic "Magnetic nanocrystals"

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Barker, Alex J., Brant Cage, Stephen Russek, Ruchira Garg, Robin Shandas, and Conrad R. Stoldt. "Tailored Nanoscale Contrast Agents for Magnetic Resonance Imaging." In ASME 2005 International Mechanical Engineering Congress and Exposition. ASMEDC, 2005. http://dx.doi.org/10.1115/imece2005-81503.

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Two potential molecular imaging vectors are investigated for material properties and magnetic resonance imaging (MRI) contrast improvement. Monodisperse magnetite (Fe3O4) nanocrystals ranging in size from 7 to 22 nm are solvothermally synthesized by thermolysis of Fe(III) acetylacetonate (Fe(AcAc)3) both with and without the use of heptanoic acid (HA) as a capping ligand. For the resulting Fe3O4 nanocrystals, X-Ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), and superconducting quantum interference device magnetometry (SQUID) is used to identify the average particle size, monodispersity, crystal symmetry, and magnetic properties of the ensembles as a function of time. The characterization study indicates that the HA synthesis route at 3 hours produced nanoparticles with the greatest magnetic anisotropy (15.8 × 104 J/m3). The feasibility of Fe8 single molecule magnets (SMMs) as a potential MRI contrast agent is also examined. SQUID magnetization measurements are used to determine anisotropy and saturation of the potential agents. The effectiveness of the Fe3O4 nanocrystals and Fe8 as potential MRI molecular probes is evaluated by MRI contrast improvement using 1.5 mL phantoms dispersed in de-ionized water. Results indicate that the magnetically optimized Fe3O4 nanocrystals and Fe8 SMMs hold promise for use as contrast agents based on the reported MRI images and solution phase T1/T2 shortening.
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Zou, Shou-Jyun, and Shun-Jen Cheng. "Magnetism of magnetic ion doped semiconductor nanocrystals." In SPIE NanoScience + Engineering, edited by Henri-Jean Drouhin, Jean-Eric Wegrowe, and Manijeh Razeghi. SPIE, 2013. http://dx.doi.org/10.1117/12.2023623.

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Youhui Gao, Zentaro Akase, Daisuke Shindo, Yuping Bao, and Kannan Krishnan. "Microstructure and magnetic properties of cobalt nanocrystals." In INTERMAG Asia 2005: Digest of the IEEE International Magnetics Conference. IEEE, 2005. http://dx.doi.org/10.1109/intmag.2005.1463769.

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Dasgupta, Papri, Sudip Mukherjee, Amitabha Ghoshray, and Bilwadal Bandyopadhyay. "Magnetic Properties Of Er[sub 2]O[sub 3] Nanocrystals Dispersed In Silica Matrix." In MAGNETIC MATERIALS: International Conference on Magnetic Materials (ICMM-2007). AIP, 2008. http://dx.doi.org/10.1063/1.2928982.

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Fescenko, Ilja, Abdelghani Laraoui, Janis Smits, Nazanin Mosavian, Pauli Kehayias, Jong Seto, Lykourgos Bougas, Andrey Jarmola, and Victor M. Acosta. "Magnetic imaging of malarial nanocrystals with diamond sensors." In Frontiers in Optics. Washington, D.C.: OSA, 2019. http://dx.doi.org/10.1364/fio.2019.jw3a.89.

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Datt, Gopal, and A. C. Abhyankar. "Structural, magnetic and dielectric properties of NiZnFe2O4 nanocrystals." In 5TH NATIONAL CONFERENCE ON THERMOPHYSICAL PROPERTIES: (NCTP‐09). American Institute of Physics, 2016. http://dx.doi.org/10.1063/1.4945159.

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Giacometti, M., L. B. Callegari, A. Collovini, M. Monticelli, C. Rinaldi, D. Petti, G. Ferrari, et al. "On-Chip Magnetophoretic Concentration of Malaria-Infected Red Blood Cells and Hemozoin Nanocrystals." In 2018 IEEE International Magnetic Conference (INTERMAG). IEEE, 2018. http://dx.doi.org/10.1109/intmag.2018.8508846.

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Peixoto, E. B., S. G. Mecena, L. S. Silva, F. A. Fabian, C. T. Meneses, and J. G. S. Duque. "CRYSTALLIZATION PROCESS AND MAGNETIC PROPERTIES OF Fe-RICH NANOCRYSTALS EMBEDDED ON AMORPHOUS MAGNETIC RIBBONS." In International Symposium on Crystallography. São Paulo: Editora Edgard Blücher, 2015. http://dx.doi.org/10.5151/phypro-sic100-031.

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Chen, Kok Hao, and Jong Hyun Choi. "DNA Oligonucleotide-Templated Nanocrystals: Synthesis and Novel Label-Free Protein Detection." In ASME 2009 International Mechanical Engineering Congress and Exposition. ASMEDC, 2009. http://dx.doi.org/10.1115/imece2009-11958.

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Semiconductor and magnetic nanoparticles hold unique optical and magnetic properties, and great promise for bio-imaging and therapeutic applications. As part of their stable synthesis, the nanocrystal surfaces are usually capped by long chain organic moieties such as trioctylphosphine oxide. This capping serves two purposes: it saturates dangling bonds at the exposed crystalline lattice, and it prevents irreversible aggregation by stabilizing the colloid through entropic repulsion. These nanocrystals can be rendered water-soluble by either ligand exchange or overcoating, which hampers their widespread use in biological imaging and biomedical therapeutics. Here, we report a novel scheme of synthesizing fluorescent PbS and magnetic Fe3O4 nanoparticles using DNA oligonucleotides. Our method of PbS synthesis includes addition of Na2S to the mixture solution of DNA sequence and Pb acetate (at a fixed molar ratio of DNA/S2−/Pb2+ of 1:2:4) in a standard TAE buffer at room temperature in the open air. In the case of Fe3O4 particle synthesis, ferric and ferrous chloride were mixed with DNA in DI water at a molar ratio of DNA/Fe2+/Fe3+ = 1:4:8 and the particles were formed via reductive precipitation, induced by increasing pH to ∼11 with addition of ammonium hydroxide. These nanocrystals are highly stable and water-soluble immediately after the synthesis, due to DNA termination. We examined the surface chemistry between oligonucleotides and nanocrystals using FTIR spectroscopy, and found that the different chemical moieties of nucleobases passivate the particle surface. Strong coordination of primary amine and carbonyl groups provides the chemical and colloidal stabilities, leading to high particle yields (Figure 1). The resulting PbS nanocrystals have a distribution of 3–6 nm in diameter, while a broader size distribution is observed with Fe3O4 nanoparticles as shown in Figure 1b and c, respectively. A similar observation was reported with the pH change-induced Fe3O4 particles of a bimodal size distribution where superparamagnetic and ferrimagnetic magnetites co-exist. In spite of the differences, FTIR measurements suggest that the chemical nature of the oligonucleotide stabilization in this case is identical to the PbS system. As a particular application, we demonstrate that aptamer-capped PbS QD can detect a target protein based on selective charge transfer, since the oligonucleotide-templated synthesis can also serve the additional purpose of providing selective binding to a molecular target. Here, we use thrombin and a thrombin-binding aptamer as a model system. These QD have diameters of 3∼6 nm and fluoresce around 1050 nm. We find that a DNA aptamer can passivate near IR fluorescent PbS nanocrystals, rendering them water-soluble and stable against aggregation, and retain the secondary conformation needed to selectively bind to its target, thrombin, as shown in Figure 2. Importantly, we find that when the aptamer-functionalized nanoparticles binds to its target (only the target), there is a highly systematic and selective quenching of the PL, even in high concentrations of interfering proteins as shown in Figure 3a and b. Thrombin is detected within one minute with a detection limit of ∼1 nM. This PL quenching is attributed to charge transfer from functional groups on the protein to the nanocrystals. A charge transfer can suppress optical transition mechanisms as we observe a significant decrease in QD absorption with target addition (Figure 3c). Here, we rule out other possibilities including Forster resonance energy transfer (FRET) and particle aggregation, because thrombin absorb only in the UV, and we did not observe any significant change in the diffusion coefficient of the particles with the target analyte, respectively. The charge transfer-induced photobleaching of QD and carbon nanotubes was observed with amine groups, Ru-based complexes, and azobenzene compounds. This selective detection of an unlabeled protein is distinct from previously reported schemes utilizing electrochemistry, absorption, and FRET. In this scheme, the target detection by a unique, direct PL transduction is observed even in the presence of high background concentrations of interfering negatively or positively charged proteins. This mechanism is the first to selectively modulate the QD PL directly, enabling new types of label free assays and detection schemes. This direct optical transduction is possible due to oligonucleotidetemplated surface passivation and molecular recognition. This chemistry may lead to more nanoparticle-based optical and magnetic probes that can be activated in a highly chemoselective manner.
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Rosenzweig, Zeev, Desheng Wang, Liane M. Rossi, Yuri A. Barnakov, and Lifang Shi. "Nanocomposite particles containing semiconductor and magnetic nanocrystals: fabrication and characterization." In Optics East, edited by M. Saif Islam and Achyut K. Dutta. SPIE, 2004. http://dx.doi.org/10.1117/12.570455.

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Reports on the topic "Magnetic nanocrystals"

1

Moler, Kathryn A. Magnetic Properties of Nanocrystals. Fort Belvoir, VA: Defense Technical Information Center, November 2005. http://dx.doi.org/10.21236/ada441687.

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Dickerson, James Henry. Structure and Magnetic Properties of Lanthanide Nanocrystals. Office of Scientific and Technical Information (OSTI), June 2014. http://dx.doi.org/10.2172/1140150.

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Sachleben, Joseph Robert. Nuclear magnetic relaxation studies of semiconductor nanocrystals and solids. Office of Scientific and Technical Information (OSTI), September 1993. http://dx.doi.org/10.2172/10120364.

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Meulenberg, R., J. Lee, and S. McCall. LDRD-LW Final Report: 07-LW-041 "Magnetism in Semiconductor Nanocrystals: New Physics at the Nanoscale". Office of Scientific and Technical Information (OSTI), October 2009. http://dx.doi.org/10.2172/971408.

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