Kita N, Shibuichi N, Sasaki S
Materials and Structure Laboratory, Tokyo Institute of Technology, Nagatsuta, Yokohama, Japan.
J Synchrotron Radiat. 2001 Mar 1;8(Pt 2):446-8. doi: 10.1107/s0909049500018409.
Synchrotron X-ray experiments on magnetic circular dichroism (XMCD) have been performed at Co K and Fe K absorption edges for CoFe2O4, Fe(1.5)Co(1.5)O4 and FeCo2O4 with the spinel structure. The XANES studies have clarified that only Fe3+ exists in all compounds and Co2+ and Co3+ coexist in the latter two cobaltites. A systematic change in XMCD spectra has concluded that the Co2+ ions in the B sites of FeCo2O4 are in the low-spin state. Since the Co2+ ions in CoFe2O4 are in the high-spin state, the spectra of the intermediate cobaltite may be explained as a mixture of low-spin and high-spin states.
利用同步辐射X射线对具有尖晶石结构的CoFe2O4、Fe(1.5)Co(1.5)O4和FeCo2O4在Co K和Fe K吸收边进行了磁圆二色性（XMCD）实验。X射线吸收近边结构（XANES）研究表明，所有化合物中仅存在Fe3+，而后两种钴酸盐中Co2+和Co3+共存。XMCD光谱的系统变化表明，FeCo2O4的B位中的Co2+离子处于低自旋态。由于CoFe2O4中的Co2+离子处于高自旋态，中间钴酸盐的光谱可解释为低自旋态和高自旋态的混合。
