Materials Literature
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Samples of Nd–Fe–B were coated with bismaleimide (BMI), a resin which is well known for its desirable barrier, mechanical, and thermal properties but has not been used as a coating material. The performance of BMI-coated samples (average coating thickness ∼15 μm) was compared with commercial epoxy-coated samples (aver…
The enhanced coercivity of ball milled nanoparticles of SmCo5 has been attributed to the reduced particle size, but the milling process introduces additional strain which can also affect the coercivity. Here the effects of size and strain are decoupled from each other using a combination of x-ray diffraction, electron…
In this article the relation between the material parameters appearing in the Preisach model and those entering the Jiles-Atherton model is discussed. Emphasis is on the variation of the anhysteretic curve and on the magnetization dependency of the pinning parameter, when changing the Preisach distribution function. T…
This article describes the advances in unification of model descriptions of hysteresis in magnetic materials and demonstrates the equivalence of two widely accepted models, the Preisach (PM) and Jiles–Atherton (JA) models. Recently it was shown that starting from general energy relations, the JA equation for a loop br…
The half metal ferromagnet CrO2 has interesting and unusual electronic properties. As in many other cases when kinetic properties are not easily described by the conventional Bloch–Boltzmann theory, strong correlation effects of the Hubbard type were called for explanation of the electronic properties of CrO2. Here we…
A new method for determining the transport spin polarization, point contact tunneling from a low temperature superconductor into a ferromagnet, is used to determine the spin polarization of several LaSrMnO thin films and crystals. The Andreev process and its utility in measurements of spin-polarization are described.…
The measurements of magnetization and magnetic anisotropy of R2Fe17 (R=Y, Er, Ho, and Gd) single crystals were performed under hydrostatic pressure up to 1 GPa, in temperature range 5–300 K and at magnetic fields up to 5 T, using the SQUID magnetometer with a miniature pressure CuBe cell. A pronounced decrease of spon…
A well-ordered surface layer of Ca on ${\mathrm{TiO}}_{2}(110)$ has been prepared by forcing Ca impurities from the bulk to segregate to the surface during annealing. The surface was studied by scanning tunneling microscopy (STM), Auger electron spectroscopy, low-energy electron diffraction, reflection high-energy ele…
One of most important issues of magnets for automobiles is thermal stability. The aim of the present work is to make clear the available temperature limit of sintered and bonded magnets for automobile applications. Thermal stability was determined by the critical temperature of 3% irreversible flux loss (T−3%φ) under…
We report on the growth of epitaxial La2/3Sr1/3MnO3 thin films on buffered Si(001) substrates. We show that a suitable choice of the buffer heterostructure allows one to obtain epitaxial (00h), (0hh), and (hhh) manganite thin films. The magnetotransport properties are investigated and we have found that the low-field…
The effects of yttria stabilized zirconia (YSZ) buffer layers for the sol-gel derived Ni–Zn ferrite thin films on SiO2/Si(100) substrates were investigated. The 500 Å thick YSZ buffer layers were found to effectively suppress the diffusion of Si into the ferrite thin films. As a consequence, films with lower Hc and hi…
Pure and ZnTi-doped spherical barium ferrite particles were prepared using two different methods: semicoprecipitation and ultrasonic spray pyrolysis. The ultrasonic spray pyrolysis method was more effective in controlling particle shape. Particle size was in between 0.27 and 0.3 μm. Coercivity and saturation magnetiza…
The structure of the hydrogen terminated, $(2\ifmmode\times\else\texttimes\fi{}1)$ reconstructed diamond (100) surface has been investigated by low-energy electron-diffraction (LEED) intensity versus energy $[I(E)]$ measurements in combination with tensor LEED calculations. It has been found that the surface correspon…
We present an analysis of recent thermal-conductivity measurements on crystalline silicon in which the concentration of the ${}^{28}\mathrm{Si}$ isotope has been increased above the natural abundance. We calculate from the phonon Boltzmann equation the change in the conductivity due to a change in isotope concentratio…
The spin and orbital contribution to the total magnetization have been measured in NiO by exploiting the polarization dependence of nonresonant x-ray magnetic scattering. Although the orbital moment is usually neglected, we observed that the orbital moment actually plays an important role with a contribution of 17% to…
We compare infrared absorption and Raman spectra of high-quality ${\mathrm{Ge}}_{1\ensuremath{-}x}{\mathrm{Si}}_{x}$ bulk crystals $(0<x<0.4).$ We use this comparison together with lattice-dynamical calculations to report on the behavior of the Ge-Ge phonon at 300 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$, to i…
SmCo based films, ≈1–3 μm thick, have been directly crystallized onto moderately heated polycrystalline susbstrates, 375 °C, by high pulse energy pulsed laser deposition. Films have been deposited to compare shadow and direct deposition. Only for shadow deposition conditions has it been possible to deposit CaCu5-type…
Energy transfer processes from Yb3+ to Tm3+ ions have been investigated in various fluoride microcrystals to examine the application limit of a simple rate equation model and to obtain methods for characterizing the host materials as to energy transfer. It has been shown that the energy transfer coefficients from dono…
A series of [La2/3Ca1/3MnO3/La1/3Ca2/3MnO3]15 multilayers, with bilayer thicknesses between 2 and 32 nm, has been prepared by pulsed laser deposition. The study of their magnetic and magnetotransport properties reveals, for the first time in this category of materials, the presence of an exchange biasing mechanism at…
The electronic structures of ${\mathrm{Nd}}_{1\ensuremath{-}x}{\mathrm{Sr}}_{x}{\mathrm{MnO}}_{3}$ with $x=\frac{1}{2}$ (high- and low-temperature phases) and $x=\frac{9}{16}$ were studied by using the rotation-invariant local spin density approximation (LSDA)+U formalism in the framework of the linear-muffin-tin orbi…