Materials Literature
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The rare earth nitrides, HoN and ErN, were synthesized by the hot isostatic pressing method. Their specific heat CH(T) and the thermal conductivity κ were measured at cryogenic temperatures. In zero field, the peak values of the C0(T) of HoN and ErN are larger than those of the magnetic regenerators such as Er3Ni. The…
This research reports the findings of large low-field magnetocaloric effect in polycrystalline Pr1−xPbxMnO3 (0.1⩽x⩽0.5) perovskites. It is found that, upon an applied field of 13.5kOe, the magnetic entropy change (ΔSM) reached values of 3.91, 3.68, and 3.34J∕kgK for x=0.1, 0.4, and 0.5 compositions, respectively. Thes…
We have investigated the carrier induced magnetic properties of anatase Ti1−x−yNbxMyO2 (M=Co,Fe) epitaxial films grown by the pulsed laser deposition technique. For Ti0.95−xNbxCo0.05O2, the n-type carrier density could be controlled in a wide range (4.9×1017cm−3to2.7×1021cm−3) by Nb doping (x=0–0.2). The temperature d…
The IV-VI diluted magnetic semiconductor Ge1−xMnxTe thin films on BaF2 (111) substrate have been prepared using solid-source molecular-beam epitaxy technique by varying the Mn concentrations from x=0.25 to 0.98. The chemical Mn concentration was determined by x-ray photoelectron spectroscopy measurement. The in situ r…
Ligand field electronic absorption and magnetic circular dichroism (MCD) spectroscopies are used to probe Co2+ dopant speciation in ZnO, ZnSe, and CdS nanocrystals and confirm the high quality of these colloidal diluted magnetic semiconductor quantum dots (DMS-QDs). Measurements of the QD giant Zeeman splittings using…
Fe and Fe3O4 nanowires have been synthesized by thermal decomposition of Fe(CO)5, followed by heat treatments. The Fe wires are formed through the aggregation of nanoparticles generated by decomposition of Fe(CO)5. A core-shell structure with an iron oxide shell and Fe core is observed for the as-prepared Fe wires. An…
The ferrimagnetic double perovskites can have high Curie temperatures TC above 600K. In the system Sr2FeMoO6 (TC≈420K) electron doping by substituting, for example, La3+ for Sr2+ ions leads to a considerable increase in TC. Here we report the same effect for LaxCa2−xCrWO6. This demonstrates that electron doping generi…
Cobalt nanoparticles with various morphologies were synthesized by thermal decomposition of cobalt acetate in the presence of various surfactants at 260°C. A combination of surfactants consisting of sufficient amount of oleic acid together with polyvinylpyrrolidone and oleylamine resulted in well-dispersed cubic cobal…
The paper deals with the problem of magnetic characterization of samples with the first-order reversal curve (FORC) diagrams. Second-order reversal curves (SORCs) are introduced in a similar manner as in the generalized deltaM experimental procedure. SORC diagrams are calculated and compared with the well-known FORC d…
In La(FexSi1−x)13, the partial substitution of Ce for La results in the decrease of the Curie temperature TC, and the isothermal entropy change ΔSm becomes larger with decreasing TC. The increase of ΔSm with decreasing TC is also confirmed by applying hydrostatic pressure, although the increment of ΔSm is not so large…
In this work, we investigated the interaction between different molecular-coated magnetite-based nanoparticles stabilized as biocompatible magnetic fluids (BMFs) and both serum albumin proteins (HSA and BSA). The investigation was focused on the fluorescence quenching of the tryptophan residue proteins after their bin…
It is known that the electric and magnetic properties of typical double-exchange materials La1−xSrxMnO3−y (LSMO) are strongly affected by oxygen nonstoichiometry y, as well as by divalent ion doping level x. In the present study, we fabricated LSMO (x=0.4) thin films on SrTiO3 (STO) (001) and LaAlO3 (LAO) (001) under…
High coercivity and magnetic viscosity in nanocrystalline YCo5 alloy were observed. The alloy was obtained by arc-melting the raw materials, mechanical milling for 4h with subsequent heat treatment for short times at 1103K and a final quenching in water. The x-ray diffraction pattern showed a single hexagonal 1:5 phas…
Cr- and Fe-doped SnO2 films were deposited on Al2O3 substrates by pulsed-laser deposition. X-ray-diffraction patterns show that the films have rutile structure and grow epitaxially along the (101) plane. The diffraction peaks of Cr-doped samples exhibit a systematic shift toward higher angles with increasing Cr concen…
Polycrystalline BiMn2O5 and Bi0.9Ce0.1Mn2O5 have been prepared by a solid-state reaction. A crystalline structure study shows that all x-ray diffraction patterns can be indexed successfully in an orthorhombic phase. Substitution of Ce for Bi ions induced in the unit cell a slight distortion and enlargement. Magnetic a…
We report the development of room-temperature ferromagnetism (FM), with coercivity Hc=2000Oe and saturation magnetization Ms∼0.01emu∕g, in chemically synthesized powders of Zn0.98Co0.02O processed at 150 °C, and paramagnetism with antiferromagnetic interactions between the Co2+ spins (S=3∕2) in samples processed at hi…
We have successfully fabricated composites consisting of aligned Fe flakes embedded in a polymer matrix. Similarly high values of permeability and permittivity have been achieved, resulting in potentially significant improvements in device miniaturization, impedance matching, and bandwidth. Various effective medium th…
We have investigated the magnetocaloric properties on the Ni2Mn1−xAxGa Heusler alloys with partial substitution of Mn by A=Co (x=0.10, 0.20, and 0.30) and Cu (x=0.15 and 0.20) in the vicinity of the martensitic transition by measuring magnetization curves at magnetic field up to 20kOe and in the temperature range of 2…
Ultrathin epitaxial films of NiFe2O4, when grown under specific conditions, show a large enhancement of their magnetic moment and electrical conductivity. This allowed us to use such layers as electrodes in magnetic tunnel junctions. In this paper, we report on the observation of a large tunnel magnetoresistance at lo…
A large positive magnetoresistance (MR) at room temperature was observed in a GaAs:MnAs granular thin film, in which MnAs nanoclusters were embedded in a GaAs matrix. Current-voltage characteristics and a MR effect of the GaAs:MnAs thin film were measured by a two-point-probe method. The MR ratio of the GaAs:MnAs gran…