G. Busch

Optical absorption of some ferro- and antiferromagnetic spinels, containing Cr3+-ions

Abstract The optical absorption of CdCr 2 S 4 , CdCr 2 Se 4 and ZnCr 2 Se 4 has been measured above and below the magnetic ordering temperatures. It has been found that the absorption edge shifts towards longer wavelengths when the substances are cooled below their Curie temperatures.

VALENCY CHANGES IN CERIUM COMPOUNDS

Abstract The magnetic susceptibilities versus temperature and magnetic moments versus applied fields of CeP, CeAs and CeSb were measured. At low enough temperatures magnetic order is observed. The valency state of the Ce ion depends on temperature.

FERRO- AND METAMAGNETISM OF RARE EARTH COMPOUNDS

The magnetic properties of the phosphides, nitrides, antimonides, and arsenides of Gd, Tb, Dy, Ho, and Er were investigated. Lattice parameters, molar paramagnetic susceptibility, magnetic moments, and critical temperatures were measured. It is shown that some of the compounds are ferromagnetic and others are metamagnetic. (C.E.S.)

Induced ferromagnetism in EuTe and GdP

Magnetic fields up to 120 k oersteds were used to induce ferromagnetic spin arrangements in normally antiferromagnetic EuTe and GdP. Ferromagnetic saturation was reached in EuTe and GdP at approximates 75 and 90 k oersteds, respectively. (C.E.S.)

Paramagnetic resonance in binary Eu(II) and Gd(III) compounds

Abstract Paramagnetic resonance has been observed in Eu(II) and Gd(III) compounds. Single absorption lines with centers near g = 2 were found in every case. The width of the lines may be explained by considering dipole-dipole and exchange interactions.

Magnetic anisotropies in HoP, HoAs and HoSb

Abstract Magnetic moments of HoP, HoAs and HoSb are measured at 1.7°K as a function of the orientation of the crystals. Strong uniaxial anisotropy is encountered in all these compounds.

Luminescence of ferromagnetic EuSe

Abstract When excited with green light EuSe shows a dark red luminescence at low temperatures. Near the Curie temperature and below the emission shifts to longer wavelengths and the intensity decreases. An applied magnetic field enhances the effect.

Effect of magnetic ordering on the photoluminescence of EuS and EuTe

Abstract The magnetic ordering semiconductors EuS and EuTe show a near-infrared photoluminescence similar to that already reported for EuSe. 1,2 In both substances an emission band of ∼ 0.2 eV half width is found at temperatures below ∼ 250°K. The luminescence is significantly influenced by either ferromagnetic or antiferromagnetic order and sensitive to a magnetic field near the magnetic ordering temperatures. On cooling, the emission of EuS is shifted towards longer wavelengths and quenched below T c , while the emission of EuTe exhibits a blue shift and an increase in intensity below T N . The dependence of the luminescence properties on magnetic ordering is interpreted in the localized magnetic polaron model already proposed for EuSe. 2

Magnetic properties of the system Zn1−xCdxCr2Se4

Abstract Magnetic susceptibilities and magnetic moments of the systems Zn 1− x Cd x Cr 2 Se 4 have been measured.

Magnetic properties of HoSb-HoTe mixed crystals

Abstract The susceptibility of mixed crystals Ho(Sb, Te) was measured between 1.7 and 300°K. Magnetic moments were determined as a function of applied field at 1.7°K. The results are discussed in terms of crystal-field and molecular-field theory.