The occupation sites of lanthanum and cobalt ions in the LaCo substituted M type ferrite Sr 1¹x La x Co x Fe 11.6¹x O 19 , where x = 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 magnetic characteristics in the LaCo substituted M-type ferrite. The results of EXAFS analysis suggest that Co is partitioned in the 4f 1 , 2a and 12k sites, which is in a good agreement with the results of the neutron diffraction analysis. XMCD measurements also indicate that the ferric ions at the tetrahedral site 4f 1 is replaced by elements of a smaller magnetic moment.

The occupation sites of calcium, lanthanum and cobalt ions in the Ca-La-Co M type ferrite Ca 0.5 La 0.5 Co y Fe 10.4-y O a , 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, 4f 1 and 12k sites in the ratio of 2:6:2 for Ca 0.5 La 0.5 Co 0.3 Fe 10.1 O a .And then it was suggested that calcium ions occupy not only the 2d site (Sr site) but also 4f 1 site (2d:4f 1 = 9:1).XMCD measurements also showed that the ferric ions at the tetrahedral 4f 1 site is replaced by elements of a smaller magnetic moment. KEY WORDSCa-La-Co M-type ferrite, magnetoplumbite type structure, neutron diffraction, EXAFS, XMCD M NdFeB Sr M SrO·6Fe 2 O 3 Sr 2+ La 3+ Fe 3+ Co 2+ Sr-La-Co M Sr 1-x La x Co y Fe 2n-y O a , a 19 1-3) Sr-La-Co M Sr 2+ Ca 2+ La 3+ Co 2+ Ca-La-Co M Ca 1-x La x Co y Fe 2n-y O a 4) Ca-La-Co M Sr Sr-La-Co M B r 0.46 T B r 5) 6)