Abstract
Abstract The results of a.c. susceptibility, d.c. magnetization and Mossbauer measurements on the insulating spinel system Ga 0.8 Fe 0.2 NiCrO 4 are reported. This system has the A sublattice diluted to below the percolation threshold and hence cannot retain any long-range ferrimagnetic order. The a.c. susceptibility shows a peak at T f ≈ 50K. For T #62; 1.5T f the magnetization is highly non-linear and tend to saturate above H #62; 2kOe. The Mossbauer spectra show broad doublets at 77 and 300 K. These observations lead to the picture of gradually evolving spin clusters ferrimagnetically coupled within, as the temperature is lowered, till the intercluster interaction brings about a cluster spin-glass ordering with randomly frozen cluster moments at T f . The absence of the Zeeman splitting in the Fe 57 Mossbauer spectra could be understood in terms of the dynamical effects arising from the thermal excitation of spin clusters.
Published Version
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