材料期刊网

The spin Hamiltonian (SH) parameters (zero-field splitting D, anisotropic g factors g(parallel to) and g(perpendicular to)) and the local structure of the trigonal Cr(3+) centers I, III and IV in CsMgCl(3) are studied using the perturbation formulae for the SH parameters for a 3d(3) ion in trigonal symmetry based on the cluster approach. In these formulae, not only the contributions from the conventional crystal-field (CF) mechanism, but also those from the charge-transfer (CT) mechanism are taken into account. According to the studies, the metal-ligand bond angle related to the C(3)-axis is found to increase from beta(H)(approximate to 51.71 degrees) in the host to beta(approximate to 54.48 degrees) in the impurity center I (in the absence of local charge compensation). As for center III (or IV), the three Cl(-) ions closest to the compensator V(Mg) (or Li(+)) are expected to displace away from the compensator by an amount Delta X(III) approximate to 0.009 nm (Delta X(IV) approximate to 0.003 nm) due to the electrostatic repulsion. The local structure of the trigonal centers and the contributions from the CT mechanism are discussed.