Materials Literature
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Composite magnets were prepared by hot pressing followed by hot deformation of blends composed of Nd14Fe79.5Ga0.5B6 or (Nd0.75Dy0.25)14Fe79.5Ga0.5B6 ribbon powders as a high-coercivity component and Fe powder as a high-magnetization component. The addition of 15 wt % α-Fe to (Nd0.75Dy0.25)14Fe79.5Ga0.5B6 increases the…
Highly coercive (Hc up to 37kOe at 300K), high remanent permanent magnets have been achieved by rapid solidification of binary Sm–Co alloys and Sm–Co alloys modified with Nb and C. Rapidly solidified SmCox alloys with x ranging from 5 to 11.5 formed predominantly a solid solution TbCu7-type SmCo7 phase, although hcp C…
We report on measurements of anisotropic magnetoresistance (AMR) (∼ρ‖−ρ⊥) along two orthogonal directions ([001] and [1−10]) of a manganite (La0.95Ag0.05MnO3) epitaxial thin film grown on a (011) SrTiO3 substrate. We show that AMR along [001] is negative whereas along the [1−10] direction is positive at low temperatur…
We report an observation of large magnetocaloric effect in clathrate compounds. Systematic dc magnetization in polycrystalline Eu8Ga16Ge30 clathrates was studied in the temperature range of 5–60 K and over an applied field range of 0–3 T. Change in entropy (ΔSmag) was calculated using the Maxwell relation from the fam…
Thick hard-magnetic films have been prepared from NdFeB microparticles dispersed in polymethylmethacrylate solutions. The preparation process included the application of different magnetic fields during the drying of the hard particles dispersion, which resulted on different degrees of out-of-plane macroscopic anisotr…
We investigate the conformation of atactic poly(sodium 4-styrene sulfonate) (PSS) molecules both in water-ethanol solutions and adsorbed to a template provided by a nanostructured monolayer of flat-lying octadecylamines on graphite. The conformations of the PSS molecules in these solutions undergo two conformational t…
Pure HfO2 and Gd-doped HfO2 thin films have been grown on different single crystal substrates (silicon, R-Al2O3, and LaAlO3) by pulsed laser deposition. X-ray diffraction (XRD) patterns show that the pure HfO2 thin films are of single monoclinic phase. Gd-doped HfO2 films have the same XRD pattern except that their di…
Hysteresis phenomenon is one of the important characteristics of soft magnetic materials. A three-dimensional (3D) magnetic property measurement system has been developed. This system can effectively control the locus of the time-varying magnetic flux density vector B and measure the corresponding magnetic field stren…
Nanocomposite intermediate rare-earth∕high-boron content hard magnetic alloys, having compositions Nd9Fe73B12.6C1.4M4 (M=Ti, V, Cr, Zr, or Nb), have been produced as melt spun ribbon. As for the Ti addition, all the other solutes were effective in modifying the crystallization behavior so that the Nd2Fe14B phase forme…
Structure and magnetic properties of Mn5Ge3−xSix pseudobinary compounds with x=0–1.5 were studied by x-ray diffraction and magnetic measurements. The compounds retain the hexagonal D88-type structure with a space group P63∕mcm, and their lattice parameters decrease from a=7.204(2)Å and c=5.028(2)Å to a=7.084(2)Å and c…
Hexagonal HoMnO3 is a frustrated antiferromagnet (TN=72K) ferroelectric (TC=875K) with a rich magnetic phase diagram consisting of multiple temperature- and field-dependent phases. Previously observed anomalies in the dielectric constant at magnetic phase transitions indicate strong coupling between the ferroelectrici…
In some circumstances, the mechanical and optical properties of multiphase brittle materials strongly depend on the level of residual micromechanical stresses that arise upon cooling due to thermal and elastic mismatch between the constituent phases. Here we study the residual internal stress in a partially crystalliz…
1-Formyldipyrromethanes are versatile precursors to porphyrins and chlorins. Two methods of synthesis of 1-formyldipyrromethanes have been investigated: (1) Vilsmeier formylation followed by selective removal of the unwanted 1,9-diformyldipyrromethane by dialkyltin complexation and (2) reaction with mesitylmagnesium b…
We fabricated fully epitaxial magnetic tunnel junctions (MTJs) using a Co-based full-Heusler alloy Co2MnGe (CMG) thin film as a lower electrode, an MgO tunnel barrier, and a Co50Fe50 upper electrode and investigated their tunnel magnetoresistance (TMR) characteristics. The microfabricated MTJs showed strongly temperat…
X -band (ν=9.4GHz) electron magnetic resonance (EMR) measurements were carried out in polycrystalline La0.4Ca0.6Mn1−xRuxO3(0⩽x⩽0.16) samples at 100K⩽T⩽550K, aiming to study magnetic/electronic ordering induced by Ru doping. EMR indicates that such doping modifies even the paramagnetic state of La0.4Ca0.6Mn1−xRuxO3 ser…
This paper reports phase components, nanostructure, coercivity mechanism, and hard magnetic properties of FePt and FePt–Ag bulk nanostructured magnets prepared by cyclic cold rolling and subsequent annealing. Annealing temperature of 500 °C or higher and annealing time of 120 min or longer are necessary for the as-rol…
The effect of high pressure on the resonance Raman spectra of the permanganate ion isolated in potassium bromide and potassium perchlorate matrices has been investigated at room temperature for pressures up to 50 kbar. The pressure dependences of the anharmonicity constants and harmonic frequencies have been determine…
Heusler alloy films Co2MnGa grown on ScErAs∕GaAs(001) substrates form stripe domains in the remnant state due to its large strain-induced out-of-plane anisotropy. The dynamics of the stripe domains has been investigated using a microstrip ferromagnetic resonance device in a broad frequency range (∼3–25GHz). In both in…
Electron time-of-flight transient photocurrents from amorphous selenium (a-Se) films were examined over the range of temperatures and applied electric fields in order to deduce a consistent model for the distribution of localized states in the a-Se conduction band tail. Superimposed on an exponential tail with charact…
We report the growth and magnetic properties of BeTe with Cr doping grown on GaAs(001) substrate at Te-rich condition by solid-source molecular-beam epitaxy. Ferromagnetisms were observed for films with high Cr concentration, x. The Curie temperatures TC for x=0.13 and x=0.17 are 175±5K, while the TC for x=0.27 is 250…