MAGNETIC-INTERACTIONS IN EXCHANGE-COUPLED PAIRS OF CHROMIUM(III) AND MOLYBDENUM(III) IONS IN CRYSTALS OF CSMX3 HALIDES

Trivalent ions tend to cluster in pairs when introduced as impurities into crystals of CsMX3salts such as CsMgCl3, CsMgBr3, and CsCdBr3. Pairs of this type which contain two paramagnetic trivalent ions behave as magnetic dimers. The EPR spectra of the Cr(III)-Cr(III) and Mo(III)-Mo(III) pairs which are formed in these crystals have been carefully analyzed. The analysis is based on exact solutions of a spin Hamiltonian written for systems which contain two magnetically coupled S = 3/2 ions. In all cases accurate spectral descriptions are obtained. The magnetic interactions between metal ions are accurately characterized by two linear exchange terms: JSi•Sj+ De(3Ŝi•Ŝj- SfSj). In these systems the exchange interactions appear to be antiferromagnetic with J values which range from 1 to 6 cm-1. © 1979, American Chemical Society. All rights reserved.