材料期刊网

By fitting the calculated EPR g(i)(i = x, y, z) factors to the observed values, the local release factor k(l) which is introduced to characterize the release (or elongation) effect of impurity-ligand bonds along the rotational axis in the cubic-to-tetragonal phase transition of ABX(3) perovskites, is obtained for the Ni+-II center in RbCaF3 crystal. The result shows that, similar to the local rotational angle (or order parameter) phi, the local release factor is unlike that of the host crystal. It suggests that in the doped crystal the impurity can affect the local phase transition behaviour in the vicinity of impurity ions.