Local atomic and electronic structures of epitaxial strained LaCoO3 thin films
Local atomic and electronic structures of epitaxial strained LaCoO3 thin films
复制标题
DOI：
10.1103/physrevb.85.020403
复制
发表时间：
2012-01
影响因子：
3.7
通讯作者：
G. Sterbinsky;P. Ryan;Jaeyoun Kim;E. Karapetrova;Jie Ma;Jing Shi;J. Woicik
中科院分区：
文献类型：
--
作者：
G. Sterbinsky;P. Ryan;Jaeyoun Kim;E. Karapetrova;Jie Ma;Jing Shi;J. Woicik
用Co-Edge X射线吸收精细结构(XAFS)谱研究了钙钛矿钴镧(LaCoO)薄膜的原子结构和电子结构。扩展的XAFS(EXAFS)表明，在高应变薄膜中，面内和面外Co-O键长的很大差异是由四方形变引起的。X射线近边吸收谱(XANES)表明，结构扭曲与Co原子和O原子的原子轨道杂化有很强的耦合关系。我们的结果表明，杂化增加并不是应变LaCoO薄膜铁磁性的原因。相反，我们认为，应变引起的氧八面体的扭曲增加了电子的布居，同时使电子的布居减少到了铁磁有序的稳定阈值以上。
We have examined the atomic and electronic structures of perovskite lanthanum cobaltite (LaCoO) thin films using Co-edge x-ray absorption fine structure (XAFS) spectroscopy. Extended XAFS (EXAFS) demonstrates that a large difference between in-plane and out-of-plane Co-O bond lengths results from tetragonal distortion in highly strained films. The structural distortions are strongly coupled to the hybridization between atomic orbitals of the Co and O atoms, as shown by x-ray absorption near edge spectroscopy (XANES). Our results indicate that increased hybridization is not the cause of ferromagnetism in strained LaCoOfilms. Instead, we suggest that the strain-induced distortions of the oxygen octahedra increase the population ofelectrons and concurrently depopulateelectrons beyond a stabilization threshold for ferromagnetic order.