Materials Literature
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The structural, electrical, and magnetic properties of the YMn2−x(Fe,Co)xO5−δ (0.0⩽x⩽1.0) pseudobinary oxides have been studied utilizing x-ray diffraction, atomic force microscopy, and magnetic measurements. Our interest in these oxides begins with the hypothesis that both ferroelectric and ferromagnetic properties c…
The presence of high frequency currents in the vicinity of metallized capacitors can generate eddy currents in the metallizations, with a possible negative impact on the reliability and lifetime of these components. These phenomena are due to the asymmetrical distribution of the field lines. We present a model derived…
Nanochannels of porous alumina films were used as nanoreactors for the reaction of hydrogen gas with a mixture of Fe nitrate and Pt chloride. This results in the formation of of FePt clusters within the nanochannels. Both the sizes of the clusters and the coercivity the cluster assembly increase with the increase of a…
We have studied magnetic anisotropy and damping in Ni81Fe19 elements of different shape and aspect ratio by time-resolved scanning Kerr effect microscopy and micromagnetic simulations. Square elements show a fourfold anisotropy that becomes weaker with increasing aspect ratio. Square elements with aspect ratio &lt…
The increase of the resistance up to two orders of magnitude under laser illumination (λ=760 nm) was observed in La0.7Ca0.3MnO3 (LCMO) epitaxial thin films in ferromagnetic state. Optical absorption also increases by 10–15 % and the magnetic second-harmonic generation signal decreases down to zero under the irradiatio…
Swelling is observed in radiation-induced amorphization of SiC, which can be attributed to both structural and chemical disordering. By first-principles calculations, an attempt is made to separate the two factors by creating complete chemical disorder with no initial structural disorder in a 64-atom supercell. By rel…
As part of our ongoing study of giant magnetocaloric compounds, we have determined the magnetic structure of Er5Si4 by high-resolution neutron powder diffraction, ac-susceptibility, and Er166 Mössbauer spectroscopy. The crystal space group is orthorhombic Pnma and the magnetic space group is Pn′ma′. The magnetic order…
Using first-principles methods, we have calculated structural and magnetic properties of face-centered (L12) and orthorhombic (Pmm2, DO19) phases of Fe3Pt and Fe3Pd. For both alloys, the L12 cubic phase was determined to be the ground state. Unlike the related Co3Pt alloy, the Pmm2 phase cannot be artificially stabili…
The field-induced antiferromagnetic phase transitions in NiCl24SC(NH2)2 have been determined in fields up to 18 T and temperatures down to 0.016 K. This is an S=1 system with a singlet ground state separated from an excited doublet by D/kB. In zero field this spin-gap system remains nonmagnetic down to T=0, because th…
The system Gd5(SixGe1−x)4 for 0.4⩽x⩽0.5 has been shown to have an unusual first order, coupled magnetic-structural phase transformation at the Curie temperature. Above the transformation temperature Tc, the material is paramagnetic with a monoclinic structure; below Tc, it is ferromagnetic with an orthorhombic structu…
A first-order phase transition in mechanically soft, nonstoichiometric Ni2MnGa oriented single crystals was achieved by the application of a magnetic field lower than 1 T on a sample with a forward martensitic transformation temperature TM of 314 K. The observed change in magnetization corresponds to a temperature dec…
The success of a room temperature magnetic refrigerator (RTMR) depends critically on two essential parts: a high magnetic field and a magnetic refrigerant material with large magnetocaloric effect. A carefully designed hollow cylindrical permanent magnet array (HCPMA) can be used to provide strong magnetic field in th…
The ac susceptibilities of NdFe11Ti and NdFe11TiH, both of which crystallize with the I4/mmm tetragonal ThMn12-type structure, have been measured between 20 and 300 K and the results reveal spin reorientations at ∼185 K and at 100±1 K, respectively. The Mössbauer spectra of NdFe11Ti and NdFe11TiH have also been measur…
Powders of Ni-Mn-Ga ferromagnetic shape memory alloy (FSMA) were produced by spark erosion. Powders quenched in liquid nitrogen are primarily hollow spherical particles, whereas those quenched in liquid argon are mostly solid spheres. Electron microscopy observations of powders as-sparked in nitrogen show highly disor…
A thorough study of the magnetic and transport properties of La0.5Sr0.5Co1−xFexO3 (0⩽x⩽0.6) compounds has been made. The Fe substitution destroys the metallic state and the resistivity increases by orders of magnitude even with a very small extent of Fe substitution. The charge localization due to Fe substitution is l…
We performed x-ray absorption spectroscopy measurements at the cobalt L2,3 edge and the oxygen K edge of Co-doped SnO2 and Co-doped TiO2. Our measurements confirm that doped cobalt atoms are in the same local environment in both compounds. Furthermore, the results support the idea that cobalt atoms occupy substitution…
The magnetic and magnetocaloric properties of Er(Co1−xSix)2 compounds with 0⩽x⩽0.075 have been studied to determine their suitability as magnetic refrigerant materials. The strength of itinerant electron metamagnetism was found to decrease with Si concentration, which is responsible for the reduction of the magnetocal…
Thin films of organic metals generally exhibit activated conductivity caused by intergrain conduction barriers. One of the few examples of thin films showing truly metallic character is TTF[Ni(dmit) 2 ] 2 . Films electrodeposited on silicon substrates remain metallic down to 12 K in spite of their polycrystalline morp…
Etching the damage of a patterned media fabricated with an artificially assisted self-assembled mask is estimated. CoCrPt thin films were etched by ion milling into aligned dots with a diameter of 40 nm. The milling condition was optimized for reducing the etching damage. As a result, the damage to the crystal lattice…
Magnetite thin films with a preferred (111) orientation have been deposited by reactive dc magnetron sputtering from a pure Fe target onto (100) GaAs substrates at 400 °C. The films show a clear Verwey transition in both the magnetization and sheet resistance as functions of temperature. For films deposited onto semic…