Cation distribution analysis of Ca-La-Co M-type ferrites by neutron diffraction, extended X-ray absorption fine structure and X-ray magnetic circular dichroism

Abstract

The occupation sites of calcium, lanthanum and cobalt ions in the Ca-La-Co M type ferrite Ca0.5La0.5CoyFe10.4-yOa, where y = 0.20 to 0.35, were analyzed by the neutron diffraction, the extended X-ray absorption fine structure (EXAFS) and the X-ray magnetic circular dichroism (XMCD) in order to understand the relationship between the local structure and the improvements of magnetization in the Ca-La-Co M-type ferrite. It was suggested that cobalt ions are partitioned in the 2a, 4f1 and 12k sites in the ratio of 2:6:2 for Ca0.5La0.5Co0.3Fe10.1Oa. And then it was suggested that calcium ions occupy not only the 2d site (Sr site) but also 4f1 site (2d:4f1 = 9:1). XMCD measurements also showed that the ferric ions at the tetrahedral 4f1 site is replaced by elements of a smaller magnetic moment.