The effect of charge-compensation vacancies in the orientation ofDtensors in Cr(III) doped hexaimidazole-zinc(II) dichloride tetrahydrate

Abstract

Single crystal E.P.R. spectra of Cr(III) doped in hexaimidazole zinc(II) dichloride tetrahydrate show the presence of a number of chemically and magnetically distinct sites with large zero-field splittings and a considerable number of forbidden transitions at X-band frequencies. The spectra at Q-band have been analysed. The number of magnetically distinct sites seems to depend on the concentration of chromium. The zero-field tensors for two of the prominent sites are (a) D = 1825·1, E = -574·3; (b) D = 1821·3, E = -388·2 (all in units of 10-4 cm-1). The unique axis of the D-tensor in both the magnetically distinct sites correspond to two of the nearest neighbour Zn-Zn directions in the lattice. Also, twinning about the bc plane is observed in these crystals.