Materials Literature
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Magnetic susceptibility studies of several A2CuBr4 salts, where A is an organoammonium cation, are reported. These salts contain tetrahedrally distorted CuBr2−4 anions. Magnetic exchange pathways exist through interanionic Br⋅⋅⋅Br pathways. In this manner, various types of new antiferromagnetic spin 1/2 magnetic syste…
The electronic structure of PtMnSb has been studied by means of the linear muffin-tin-orbital method of band-structure calculation. In agreement with earlier investigations a so-called half-metallic behavior has been found. Until now, this exotic feature of the band structure of PtMnSb, which is made responsible by so…
The crystal structure of fructose-1,6-bisphosphatase (EC 3.1.3.11) complexed with the product fructose 6-phosphate (F6P) has been refined at 2.1-A resolution to an R factor of 0.177 with root-mean-square deviations of 0.014 A and 2.9 degrees from the ideal geometries of bond lengths and bond angles, respectively. The…
We have examined incident-beam effects in electron-stimulated Auger-electron diffraction (AED) on a cleaved GaAs(110) surface. The results indicate that incident-beam diffraction is significant in an AED experiment, and that the dissipative nature of the incident beam in contributing to the Auger process must be accou…
In situ crystallized barium hexaferrite films have been deposited with a target-facing sputtering system under previously optimized conditions on four different substrates which are: SiO2, ZnO, Gd3Ga5O12, and Al2O3. By using several structural and magnetic characterizations different growth mechanisms were put forward…
We have imaged ten different superstructures on highly oriented pyrolytic graphite near adsorbed platinum particles using a scanning tunneling microscope. These superstructures are localized in small areas near the platinum particles and decay within a distance of 2--5 nm into the graphite lattice. When Fourier transf…
Thin Si films on thermally grown ${\mathrm{SiO}}_{2}$ layers were completely melted by pulsed-laser irradiation. The molten films cool very rapidly (>${10}^{9}$ K/s) until bulk nucleation initiates solidification. The quench rate was varied by changing the thickness of the Si or the ${\mathrm{SiO}}_{2}$ layers. For…
The two-photon absorption (TPA) spectrum of interacting \ensuremath{\pi} electrons in conjugated polymers is shown to be qualitatively different from any single-particle description, including the Hartree-Fock limit. Alternating transfer integrals t(1\ifmmode\pm\else\textpm\fi{}\ensuremath{\delta}) along the backbone…
The Brown paradox1 concerns an order of magnitude discrepancy between micromagnetic theory and experiments: the theoretical nucleation field for an elongated iron specimen is −500 Oe whereas the measured value for high-quality iron whiskers is about 0.1 Oe. It is a fairly widespread view that the paradox may be resolv…
A generalization of the vector Preisach hysteresis model is proposed. This new vector hysteresis model represents a larger class of hysteresis nonlinearities than either the Stoner-Wohlfarth model or the previously developed vector Preisach model. To demonstrate this fact, it will be shown that the Stoner-Wohlfarth mo…
PNb 9 O 25 cristallise dans I4/m avec a=15,639, c=3,8317 A, Z=2; affinement jusqu'a R=0,031. Le reseau est compose de colonnes 3×3×∞ du type ReO 3 . Chaque colonne possede des sommets communs avec les quatre colonnes voisines et des cotes communs avec les tetraedres PO 4
The temperature dependence of the magnetic susceptibility for 1.5<T<300 K, the field dependence of the magnetization M(H), for 0<H<23 T and 1.5<T<15 K, and the temperature dependence of the heat capacity C(T), for 5<T<95 K are reported for the insulating distorte…
A new form for the classical Preisach model of hysteresis which gives the decomposition of this model into reversible and irreversible components is derived. This form reveals that the classical Preisach model does describe (to a certain extent) reversible properties of hysteresis nonlinearities. It is also shown that…
We have explored the impact of low-level Cu additions on the magnetic properties of melt-spun Nd-Fe-B ribbons. The addition of 0.5 at. % Cu enhances the intrinsic coercivity as much as 30% over that of Cu-free materials. Transmission electron microscopy analyses demonstrate that Cu segregates preferentially to the int…
In general, the stoichiometry of melt-spun ribbons and subsequent hot-worked Nd-Fe-B magnets derives from the composition of the starting ingot. We have shown, however, that it is possible to introduce small amounts of powdered metals into the ribbons after the ingot has been melt spun. Many elements, when mixed with…
6.5% Si steel is widely known as an excellent soft magnetic material because its magnetostriction is nearly zero. The ac magnetic properties and magnetostriction of 6.5% Si steel sheet were evaluated and compared with those of conventional 3% Si steel sheet. From these data, this sheet is considered to be one of the b…
There has been limited work on the effects of alloying elements on the properties of hot-worked anisotropic magnets. The coercivity mechanisms for sintered and rapidly solidified Nd-Fe-B magnets are different, and additives can have different effects on magnetic properties. The present study was conducted to clarify t…
By numerical simulations treating the motion of a charged soliton in polyacetylene, we analyze the width of a moving soliton. The motion of the soliton is induced by applying an electric field as in the previous work. The soliton width is estimated by two methods; one is from the excess charge density profile and the…
We discuss a generalization of the Preisach model, based on the assumption that each point (α,β) of the Preisach plane corresponds to a small correlation region of the system cross section, inside which magnetic flux reverses at a rate Φ̇ ∝ Ha − α (or Ha − β) when the applied field Ha exceeds the threshold α (or β). W…
The powerful magnet materials based on rare earth (R) and magnetic 3d metals (M=Fe,Co) exhibit a large affinity to absorb hydrogen. Hydrides of the anisotropic materials R2M17 and R2M14X with X=B, C, and RM12 with M=Fe1−xM′x, have been systematically investigated. First, the impact on the fundamental properties (struc…