Materials Literature
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The rare-earth–iron intermetallic compounds SmTiFex, with x ranging between 8 and 10, have been synthesized by an arc-melting technique. We found that they crystallize in the ThMn12-type tetragonal structure, I4/mmm. Unusual uniaxial magnetocrystalline anisotropies have been observed. The c axis is the easy magnetizat…
Single crystals of the compounds R2Fe14B some 1–4 mm in size have been grown for a study of the anisotropy of the magnetization curves. These curves for crystals with R=Tb, Dy, Ho, Er, and Tm were measured at the Service National des Champs Intenses, Grenoble, between 4.2 and 275 K, with fields of 0–18 T being applied…
We examine theoretically structural and electronic properties of thin ${\mathrm{Si}}_{\mathrm{n}}$${\mathrm{Ge}}_{\mathrm{n}}$ superlattices for n=1, 2, 4, and 6, grown on (001)-oriented substrates. The increased repeat distance along the growth direction leads to folding of conduction-band states to the \ensuremath{\…
Low-field thermomagnetic analysis of sintered Nd(Dy)-Fe(Co)-B magnets provides new evidence that the high coercivity near room temperature is due to the pinning of residual domain walls in a ferromagnetic grain-boundary phase. The temperature where MHc drops to near zero appears to be the Curie point of that phase. It…
Spin-echo nuclear magnetic resonance was used to study 59Co hyperfine fields in the intermetallic compounds RCo12B6 with R=Y and Gd. Two groups of signals were obtained and interpreted in terms of anisotropic orbital contributions to the hyperfine field in the domain walls and domains.
The elements Dy and Al play very important roles in the magnetic properties of Nd-Fe-B base compounds. The proper combination of Dy and Al may provide a significant improvement in the magnetic properties. With this in mind, close examinations have been made of the magnetic properties of several (Nd,Dy)-(Fe,Al)-B alloy…
Present works describe the development of Fe-Cr-Co-Mo alloys with favorable {110}〈100〉 texture, which will lie along the transverse direction (TD) of the rolled strips. The studied alloy composition is Fe-30 wt. % Cr-15 wt. %Co-3 wt. % Mo-0.1 wt. % Mn-0.05 wt. % S. The magnetic properties of the alloys have been enhan…
It is shown from the ${M}_{4}$,5${\mathrm{N}}_{4}$,5X (X=${O}_{1}$,${O}_{2}$,3,${N}_{6}$,7) Auger emissions of La metal, ${\mathrm{La}}_{2}$${\mathrm{O}}_{3}$, and ${\mathrm{LaF}}_{3}$ that the 4f hole pulled down below the Fermi level by the 3d core hole in La metal is significantly populated before Auger decays take…
The 4f core level spectra of ThO2, UO2, and NpO2 are shown to be well described in the Anderson impurity model. The O(2p)-actinide (5f ) hybridization is found to be very large. This leads to a new interpretation of the 7-eV satellite in the 4f spectrum, which corresponds to an antibonding 5f n−5f n+1 final state, whe…
Isotropic and anisotropic vector Preisach models of hysteresis are described. The identification problems of fitting these models to experimental data are posed. It is shown that the above problems can be reduced to the solution of special integral equations. Analytical techniques for the solution of these integral eq…
We present a treatment of the scattering of electromagnetic waves at rough dielectric surfaces using both the Rayleigh hypothesis and the extinction theorem. An explicit expression relating s- and p-polarized components of the field in the dielectric with the incident field is given. A Dyson equation is then derived f…
A structure model of an icosahedral Al-Mn quasicrystal is proposed based on the structure-factor calculation and the x-ray and neutron powder-diffraction patterns of rapidly solidified Al-Mn alloys. The model has a local atomic arrangement similar to that of the cubic \ensuremath{\alpha}--Al-Mn-Si and has icosahedral…
A series of NMR experiments has been conducted on $^{1}\mathrm{H}$ in the metallic glass a-${\mathrm{Zr}}_{3}$${\mathrm{RhH}}_{3.5}$ to establish the temperature dependence of the mean H-atom jump rate. Temperature and frequency dependence of the $^{1}\mathrm{H}$ spin-lattice relaxation rates and, at three temperature…
A simple model used previously by the authors to explain stress variation of magnetic hysteresis is now employed to explain the effect of stress on the amplitudes of the first- and third-order harmonics of the magnetic induction signal resulting from application of an ac magnetic field of low frequency to a steel spec…
We study surface orientation of nematic 5 CB on obliquely SiO evaporated glass plates, at grazing incidence. For SiO thickness comparable with nematic molecular length, we observe a twofold degenerate oblique orientation, which allows a continuous transition between the well-known planar and oblique orientations. This…
Reactive sticking coefficients (RSCs) were measured for silane and disilane on polycrystalline silicon for a wide range of temperature and flux (pressure) conditions. The data were obtained from deposition-rate measurements using molecular beam scattering and a very low-pressure cold-wall reactor. The RSCs have nonlin…
The hard magnetic properties of Fe-Mm-B alloys have been studied in melt-spun ribbons and sintered magnets. The as-spun ribbons were magnetically soft and high coercive fields (Hc∼7 kOe) were obtained after a heat treatment at about 700 °C. This caused crystallization of the sample into the Mm2Fe14B phase. The magneti…
Permeability relates the magnetic field intensity in a magnetic material to the resulting flux density. The initial part of the permeability extending from dc fields to the radio-frequency fields of a few hundred megahertz is due to domain wall displacement. A spin resonance occurs due to the presence of an anisotropy…
We apply spin-density functional theory (SDF) to describe noncollinear magnetism; i.e., self-consistent energy-band calculations based on the local approximation to SDF theory are presented in which the magnetization associated with different atoms in a unit cell is allowed to point along different, noncollinear direc…
The parameter dependence of vacancy and self-interstitial formation energies has been studied with an analytic nearest-neighbor atomistic model based on the embedded-atom method. The model was designed for fcc copper, but the results should not depend on either the structure or the element. Exponentially decreasing fu…