Defect induced low temperature ferromagnetism in Zn1-xCoxO films
Defect induced low temperature ferromagnetism in Zn1-xCoxO films
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DOI：
10.1063/1.2713935
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发表时间：
2007-04
影响因子：
3.2
通讯作者：
E. Biegger;M. Fonin;U. Rüdiger;N. Janssen;M. Beyer;T. Thomay;R. Bratschitsch;Y. Dedkov
中科院分区：
文献类型：
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作者：
E. Biegger;M. Fonin;U. Rüdiger;N. Janssen;M. Beyer;T. Thomay;R. Bratschitsch;Y. Dedkov
我们对磁控溅射制备的外延 Co 掺杂 ZnO 薄膜的结构、磁性和光学性质以及电子结构进行了详细研究。采用不同的制备条件来控制 ZnO 基质晶格中氧空位的浓度。磁化测量表明在贫氧条件下制备的样品在低温下的铁磁行为，而在富氧条件下制备的样品显示出极小的铁磁信号，证实了 Zn1−xCoxO 中的铁磁性与氧相关缺陷的存在相关。 Co L2, 3 边缘的 X 射线吸收光谱 (XAS) 以及光学透射率测量表明，Co 离子在四面体对称性下以高自旋 Co2+ (d7) 态存在，表明在 ZnO 主晶格中正确结合。在不同条件下制备的样品的 O K 边缘 XAS 谱图的比较表明，结构发生了显着变化。
We present a detailed study on the structural, magnetic, and optical properties, as well as the electronic structure of epitaxial Co-doped ZnO films prepared by magnetron sputtering. Different preparation conditions were implemented in order to control the concentration of oxygen vacancies in the ZnO host lattice. Magnetization measurements indicate ferromagnetic behavior at low temperature for samples prepared at oxygen-poor conditions whereas the samples prepared at oxygen-rich conditions show extremely small ferromagnetic signal corroborating that ferromagnetism in Zn1−xCoxO correlates with the presence of the oxygen-related defects. X-ray absorption spectroscopy (XAS) at the Co L2, 3 edge together with optical transmittance measurements show that Co ions are present in the high-spin Co2+ (d7) state under tetrahedral symmetry indicating a proper incorporation in the ZnO host lattice. Comparison of the O K edge XAS spectra of the samples prepared at different conditions show substantial changes in the s...