Materials Literature
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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…
Under oxidizing preparation conditions the magnetite (111) surface reconstructs to a highly ordered superlattice. This surface reconstruction represents an oxygen termination of the magnetite bulk. We employ spin-polarized (SP) scanning tunneling magnetization (STM) to study the spin-dependent tunneling between a magn…
Electrical, magnetotransport, and magnetization measurements have been carried out on half-doped (La0.5−xTbx)(Ca0.38−ySr0.12+y)MnO3 (0.025⩽x⩽0.125; y=0.8x) compounds. The increase in Tb3+ and Sr2+ contents keeps the average A-site ionic radius constant at ∼1.215 Å but introduces increasing size disorder. The insulator…
Tensile and compressive loading experiments were conducted at room temperature on a thin slab (1 mm) of Ni50Mn33Ga17 single crystal ferromagnetic shape memory alloy while subjected to cyclic magnetic field (up to 550 kA/m). Tensile loads ranged from 0.4 MPa to 0.8 MPa while compressive loads ranged from 0.4 MPa to 2.2…
Polycrystalline Fe52Pt48 alloy thin films were prepared by dc magnetron sputtering on preheated natural-oxidized silicon wafer substrates. The film thickness was varied from 10 to 100 nm. The as-deposited film was encapsulated in a quartz tube and postannealed in vacuum at various temperatures for 1 h, then furnace co…
Strictly stress-induced magnetization reversal in magnetostrictive Co50Fe50/Co80B20 multilayers was studied by magneto-optical Kerr microscopy. The remagnetization takes place by rotational processes in externally applied stress in the absence of magnetic fields. Multiple small-angle domains develop at low magnetic an…
The magnetic and crystal structures of the series FexMn5−xSi3 (x=4,3.5,3,2,1) have been reinvestigated by neutron powder diffraction between 315 and 8 K. Fe atoms are found to preferentially occupy the 4d site of the hexagonal D88 structure (P63/mcm). The compound Fe4MnSi3 orders ferromagnetically below 300 K. Refinem…
Diverse chain foldings of a semi‐conjugated polymer are examined with submolecular resolution and molecular models (see Figure) are proposed. The ordering process observed directly supports the hypothesis that the polymer would show a preference to adsorb “straight” on a nanotube surface. The results provide important…
The transport properties of A2BMoO6 (A=Ca, Sr, and Ba; B=Cr, Mn, and Fe) crystals are investigated from studies of x-ray diffraction, thermoelectric power (TEP) S, and resistivity ρ measurements over a wide temperature range (20–900 K). The resistivity of A2FeMoO6 (A=Ca, Sr, and Ba) crystals shows a metallic character…
Domain structures in patterned magnetostrictive NixFe1−x films are observed by Kerr microscopy. The micrometer-thick films display different types of domain patterns varying with saturation magnetostriction. In negative magnetostrictive and tensile-stressed films, regular closure domains are replaced by edge curling w…