Spin Glass Freezing of V_xCr_3−xS₄

Abstract

Polycrystalline samples of V_xCr_3−xS₄ (0<x<2) are prepared and their magnetic properties are studied by magnetization and AC-susceptibility measurements. Magnetic phase diagram is determined. For 0<x<x_c (slightly larger than 0.6), the compounds enter into an antiferromagnetic state at T_N, and gradually enter into frozen-spin state around T_f(<T_N). The compound with x=0.4 shows a symmetric hysteresis loop at 4.2 K after being cooled under magnetic field from above T_f. For x_c<x<2, on the other hand, there is a sharp paramagnetic-spin glass transition at T_g. The compound with x=1.0 shows an asymmetric hysteresis loop at 4.2 K after being cooled under magnetic field from above T_g. It is suggested that the appearance of the asymmetric loop depends on a long-distance correlation between the spins, which is realized for x=1.0 as a result of the thermodynamical phase transition at T_g.