Cation distribution and exchange interactions in CuCr2S4:57Fe

The character of the distribution of Fe ions over tetrahedral and octahedral positions of the spinel structure was investigated in the magnetic-hardening range at 290 and 78 K in CuCr₂S₄:⁵⁷Fe with different degrees of doping with the isotope⁵⁷Fe. It was established that for degrees of substitution not greater than 0.1 per formula unit the Fe ions do not have a definite preference for either positions. The dependence of the effective magnetic field at the⁵⁷Fe nuclei on the degree and character of the embedding of Fe ions in the crystal lattice was determined. The features found are explained by the change in the indirect exchange of Cr ions via current carriers and the degree of delocalization of the 3d-electrons of Cr and Fe ions in the process of cationic substitution.A. N. Tupolev Aviation Institute, Kazan. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 71–74, October, 1992.