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A new thiospinel CuCrZrS 4 has been successfully synthesized by a solid-state chemical reaction. This CuCrZrS 4 exhibits ferromagnetic properties below the Curie temperature at T c = 60 ± 2 K. The appearance of irreversibility between field-cooled (F.C.) and zero-field cooled (Z.F.C.) magnetization is prominent below around 5 K in less than 150 Oe. The ac susceptibility χ AC shows a rapid decrease below ≈10 K. This low-magnetic field behaviour indicates the existence of a reentrant spin glass phase below ≈10 K. The d.c. magnetic susceptibility above 100 K shows Curie-Weiss behaviour with the effective magnetic moment of 3.61 µ B , which is a little less than the spin only value of 3.87 µ B for Cr 3+ ion. The asymptotic Curie temperature θ p is approximately 65 K which is a little higher than T c. The valence state is confirmed to be Cu + Cr 3+ Zr 4+ S 2-4 on the basis of magnetic properties. Electrical resistivity ρ shows a semiconducting temperature dependence over the temperature range 4.2 to 280 K with an activation energy of 6.84×10-3 eV in the higher temperature range 50 to 283 K.

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Ferrimagnetic order in the mixed rare-earth iron garnet {Y 1-x Gd x } 3 Fe 5 O 12 system has been reinvestigated to cover the temperature range 5.0 to 700 K. The magnetization versus temperature exhibits a systematic variation with changing concentration x. The ferric-ion exchange coupling is strong enough to determine the Curie temperature ≈ 559 K for all the values x. The compensation temperature at which the magnetization crosses zero (shows the minimum) demonstrates the applicability of the three-sublattice model.

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