Materials Literature
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The high-frequency dielectric-constant tensor and the Born effective charge of ${\mathrm{TiO}}_{2}$ rutile are calculated using variational density-functional perturbation theory. The calculated structural properties and high-frequency dielectric constant show agreement with experiments at the level of a few percent.…
We have performed energy-band calculations of X 2 Mn 1- x V x Si (X=Fe and Co) at x =0, 0.25, 0.5, 0.75, 1.0. In ferromagnetic ordering, we obtain excellent agreement between calculated and experimental data for the magnetic moment per formula unit and the lattice constant, at each Mn content. We have obtained the res…
In this concise overview, the physical principles of magnetic Barkhausen effect will be briefly discussed and its recent applications in material characterization will be considered. There are new trends in micromagnetic Barkhausen effect emissions and its applications in the material characterization area. These emis…
Magnetic and microstructural investigations of some polycrystalline rare-earth—transition-metal (RE-TM) alloy thin films are reported. Emphasis was placed on pseudobinary alloys in the (TbxDy1−x)Fe2 and (TbxDy1−x)3Fe4 systems. The films were prepared by sputter deposition onto both room-temperature and high-temperatur…
Temperature-dependent magnetic properties of nine NdFeB sintered magnets with various Co-Nb, Co-V, or Co-Mo additions have been measured up to 175 °C using both closed-loop and open-circuit methods. The irreversible loss of induction, reversible temperature coefficient of induction (α), and temperature coefficient of…
We have carried out a quantitative low-energy electron-diffraction intensity analysis of the Ge(111) \ensuremath{\surd}3 \ifmmode\times\else\texttimes\fi{} \ensuremath{\surd}3 R30\ifmmode^\circ\else\textdegree\fi{}-Ag structure. It is found that the Ag atoms arrange according to a honeycomb chained trimer model (HCT)…
Quantitative measurements of the effects of pressure on the kinetics and quality of diamond films grown with hot-filament chemical-vapor deposition are reported. Pressure affects growth kinetics largely because it affects transport of precursors to the growing surface. H and CH3 concentrations at the growth surfaces a…
We report the valence-band and Co 2p photoemission spectra of ${\mathrm{LaCoO}}_{3}$ obtained at different temperatures (100, 300, and 573 K). Analysis of the core-level spectrum in terms of a configuration interaction model suggests that both low- and high-spin states coexist at the low temperature (100 K). It also i…
It is shown through theoretical considerations on stochastic domain wall motion in a perturbed medium with quenched-in disorder that the Barkhausen signal v, as well as the size Δx and duration Δu of Barkhausen jumps follow scaling distributions of the form v−α, Δx−β, Δu−γ, where α=1−c, β=3/2−c/2, γ=2−c, and c is prop…
Using molecular beam epitaxy and ion implantation, Japanese workers have formed Fe16N2 in thin Fe films. They report a large magnetic induction for this nitride, ≥2.8 T. In the present study, Fe16N2 has been prepared in bulk form by treating Fe powder with NH3/H2 gas mixtures at temperatures in the range 660–670 °C. T…
Giant magnetostrictive thin films of both the binary compound TbxFe1−x and the ternary compound (TbyDy1−y)xFe1−x have been prepared by multitarget magnetron sputtering in wide compositional ranges. In view of their potential use as actuators in microsystem technology the research was focused on low-field magnetostrict…
The electrical conductivity of polycrystalline mixed ferrite system having the chemical formula MnxZn1−xFe2O4 (where x=0.0, 0.2, 0.4, 0.6, and 0.8) was investigated from room temperature to the neighborhood of the Curie temperature by the two-probe method. The electrical conduction in these ferrites is explained on th…
We have discovered that the substitution of Ga or Si for Fe in Sm2Fe17Cx helps the formation of high-carbon rare-earth iron compounds with 2:17-type structure. We have succeeded in preparing Sm2Fe15M2Cx (M=Ga, x=0, 1.0, 2.0, and 3.0; M=Si, x=0, 0.5, 1.0, and 1.5) compounds with Th2Zn17-type structure by arc melting. T…
The interpretation of interaction through Henkel plots and Δm plots has become popular in recent years; however, the demagnetized state is often not specified. In this paper, the demagnetized state dependence of Henkel plots is calculated using the classical Preisach model, the moving model, and the complete-moving-hy…
High isotropic remanences and energy products have been obtained in melt-spun Nd-Fe-B samples with a fine grained mixture of α-Fe and Nd2Fe14B1 containing more than 50 wt % of α-Fe. Reduced remanences as high as 0.78 with high saturation magnetization (190 emu/g) led to (BH)max of 14 MGOe. The coercivities varied from…
In this paper we report on Schottky barrier height measurements of nickel on both diamond (111) and (100) surfaces, as a function of surface preparation. The Schottky barriers of thin (5 \AA{}) nickel films on natural type-IIb (p-type semiconducting) diamond (111) and (100) surfaces were determined with ultraviolet ph…
Using rapid thermal processing (RTP) we recently demonstrated the production of high quality well ordered barium ferrite films in times much shorter than those required by a conventional annealing process. Influence over the magnetic and structural properties developed in annealed samples was also achieved by variatio…
The influence of Si, Co, and Dy2O3 on magnetic properties of sintered 40Cedidymium–Fe–B magnets was investigated and related to the microstructure through transmission electron microscopy (TEM) investigations. It is found that the decrease in iHc and Tc caused by the presence of Ce in the 40Cedidymium could partly be…
The magnetic and structural properties of mechanically alloyed Nd2Fe14B+ (Fe, FeCo) powders have been investigated over a wide range of temperatures. X-ray diffraction patterns on samples milled for 48 h showed that the powders had a two-phase structure consisting of a disordered Nd-Fe-B alloy and α-Fe with a fine gra…
The current-voltage characteristic of polycrystalline titanium-substituted lithium ferrites has been measured at temperatures above room temperature. At voltages below a critical value an Ohmic relationship is observed, while it obeys a power-law relationship (i∝Vα, where α is a temperature-dependent constant) above t…