Percolation limit and stability conditions for the spin glass state in the spinel families based on the two matrices CuCr(2)S(4) and CuCr(2)Se(4) doped by Sb ions.

The percolation limit of the appearance of the spin glass state in the compounds under study has been obtained experimentally. The conditions of stability of the spin glass state have been analyzed here on the basis of the de Almeida-Thouless theory for two spinels differing in the magnetic coupling constants. It turned out that for the higher value of the coupling constant the magnetic field influences the freezing temperature more strongly.