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Arc melting and reaction sintering of Cu, Ag, Au with Zn, Cd, Hg yields new compounds of the form RE6Fe13X, where X may be Cu, Ag, Au, Zn or Hg. The compounds are produced only after heat treatment at 600 degrees centigrade in silicon capsules. All the compounds produced by this method have the same curie temperature, which is equal to the room temperature. The Fe sublattice exhibits ferrimagnetic couplings, which produce very low magnetization.

Production methods for obtaining the metastable La[Fe.sub.12] [O.sub.19] are described. The magnetic properties of La-substituted Sr hexaferrite and pure La[Fe.sub.12][O.sub.19] are summarized. The uniaxial anisotropy of La[Fe.sub.12][O.sub.19] increases dramatically with decreasing temperature. This is attributed to a change of the [Fe.sup.3+] to an [Fe.sup.2+] on the 2a site which is confirmed by Mossbauer spectroscopy. This leads to a semiconductor behavior visible in the temperature dependence of the electrical resistivity. Index Terms--Hexaferrites, magnetocrystalline anisotropy, Mossbauer spectroscopy.

In hexaferrites of the composition Sr[Fe.sub.12][O.sub.19] (SrM), Sr was substituted by R = La, Sm, and Nd. The precursors were weighed according to different [Sm.sup.3+]/[Sr.sup.2+] ratios (n = [Sm.sup.3+]/[Sr.sup.2+]), where n was varied between 1/16 and 1/2. The samples were produced by hydrothermal synthesis. The effects of the rare earth substitution on the magnetic properties were investigated, measuring magnetization and magnetocrystalline anisotropy but also applying Mossbauer spectroscopy and nonmagnetic resonance. Nd and Sm substitution increases the intrinsic coercivity without causing any significant deterioration in either the saturation magnetization or the remanence, whereas La substitution has only a small effect on the intrinsic coercivity of SrM. Index Terms--Hydrothermal synthesis, La substitution, magnetic properties, Nd, Sm, Sr hexaferrite.

The influence of the local cooling rate on the magnetic properties is studied by measuring the temperature dependence of the ac susceptibility and hysteresis loops. The anomaly in the susceptibility curve and the kink at low fields in the hysteresis loops disappear by removing the wheel side ribbon surface. [sup.57]Fe Mossbauer spectroscopy also showed some change in the hyperfine field distribution upon removing of the surface. Index Terms--Hard magnetic materials, melt-spun ribbon, Mossbauer spectroscopy, susceptibility.

The effect of the volume expansion on the total linear magnetostriction of Fe85Ga15, Fe80Ga20, and Fe71Ga29 mold-cast bulk alloys was investigated by measuring the change in length with applied field longitudinal and perpendicular to the temperature gradient during solidification. In the magnetically saturated state, due to the contribution of the volume expansion, the saturation magnetostriction for all three alloys was about 66 % of the total linear magnetostriction. The magnetostriction is strongly dependent on the direction of the temperature gradient, being larger in this direction. The substitution of Fe by Ga atoms increases the lattice constant and causes a change to the A2 crystal structure, which was confirmed by Mössbauer spectroscopy. The thermal-expansion coefficient increases with Ga content at temperatures between 4.2 and 150 K. [ABSTRACT FROM AUTHOR]

Singular point detection technique and the a.c.-susceptibility measurements have been used to determine the temperature dependence of the magnetocrystalline anisotropy field from 4.2 K to the Curie temperature and the temperature-induced magnetic phase transition of R[Fe.sub.11]Ti and R[Fe.sub.10][V.sub.2] compounds. A comparison of the magnetic properties of these two series compounds has been made in details.

The local magnetic structure of FeTb multilayered thin films was analyzed using magnetic circular x-ray dichroism studies. The results showed that an interface region with a chemical structure similar to that of intermetallic compounds made substantial contributions to the magnetism. The magnetic spectra at the Tb L2 edge and the Fe K edge allowed data on the binding characters of the magnetized environment to be obtained.