MAGNETIC AND ELECTRICAL PROPERTIES OF CO1-XCUXRH2S4

Samples of Co1-xCurRh2S4 with 0.1 ≦ x ≦ 1 show a practically temperature-independent resistivity of 10-2-10-3Ω cm and a positive Seebeck coefficient decreasing from 125 μV/deg for x = 0.1 to ≈25μV/deg for 0.5 ≦ x ≦ 1. The material is antiferromagnetic for 0 ≦ x < 0.4, shows spontaneous magnetization for ≈0.4 ≦ x ≦ ≈0.7 and is paramagnetic for ≈0.7 ≦ x ≦ 1. The strongest spontaneous magnetization occurs at x = 0.5 and a moment of ≈0.8 μB/molecule is found. The conduction is attributed to holes in the valence band. The occurrence of a small saturation moment in the composition range 0.4 ≦ x ≦ 0.7 is explained tentatively and attributed to double exchange between Co2+ and Co3+ on tetrahedral sites. © 1969.