Origin of magnetism in cobalt-doped indium tin oxide thin films
Origin of magnetism in cobalt-doped indium tin oxide thin films
复制标题
DOI：
10.1103/physrevb.82.144429
复制
发表时间：
2010-10-20
影响因子：
3.7
通讯作者：
Dhesi, S. S.
中科院分区：
文献类型：
--
作者：
Hakimi, A. M. H. R.;Schoofs, F.;Dhesi, S. S.
我们报告的X射线吸收光谱（XAS）和X射线磁圆二色性（XMCD）的研究，5.4原子。%的Co掺杂的氧化铟锡（ITO）薄膜显示出超过室温的铁磁性。在Co L（2，3）边的XAS光谱显示出明显的二价八面体配位Co（2+）离子的多重峰特征。结果表明，Co（2+）离子为非金属离子，取代了ITO中的In位。磁场和温度依赖的XMCD光谱意味着Co（2+）离子在近表面区域和整个大部分的膜的整体铁磁响应的顺磁贡献。在In M（2，3）或Sn M（2，3）边缘没有检测到磁极化。因此，我们假设所观察到的铁磁性是主机ITO的sp带和过渡金属Co掺杂剂的局部d电子之间的sp-d交换相互作用的结果。
We report an x-ray absorption spectroscopy (XAS) and x-ray magnetic circular dichroism (XMCD) study of a 5.4 at. % Co-doped indium tin oxide (ITO) thin film shown to exhibit ferromagnetism beyond room temperature. The XAS spectra at the Co L(2,3) edge reveal pronounced multiplet features characteristic of divalent octahedrally coordinated Co(2+) ions. The results suggest that the Co(2+) ions are nonmetallic and substitute for the In site in ITO. Magnetic field and temperature-dependent XMCD spectra imply that the Co(2+) ions give a paramagnetic contribution to the overall ferromagnetic response both at the near-surface region and throughout the bulk of the films. No magnetic polarization was detected at the In M(2,3) or Sn M(2,3) edges. We therefore presume that the ferromagnetism observed is a result of the sp-d exchange interaction between the sp band of the host ITO and that of the localized d electrons of the transition-metal Co dopants.