Dynamic Susceptibility of Thiochromite FeCr2S4

The magnetic susceptibility of the ferrimagnet FeCr2S4 was studied by a dynamic method in order to highlight the nature of a magnetic transition in the region of T = 60 K. The properties of the compound were measured in zeroth DC magnetic field НDC = 0 in the temperature range 4–230 K at the modulation amplitudes НАC = 1 and 17 Oe and the AC frequencies ν = 10, 100, 1000, and 10 000 Hz. At T > 60 K, the properties of FeCr2S4 correspond to the long-range ferrimagnetic order with local spin disorder. Spin lattice distortions (microareas or magnetic clusters) strongly increase in the region of 150 K, where a local spin glass appears with the spin freezing temperature Tf = 155 K. The flat maximum of the impurity spin glass in FeCr2S4 at T = 155 K can be considered as a mere assembly or conglomerate of especially large magnetic clusters with the effective Curie temperature T = 155 K.