Zhang Fei, Wu Biao, Zhou Guowei, Quan Zhi-Yong, Xu Xiao-Hong
Key Laboratory of Magnetic Molecules and Magnetic Information Materials of Ministry of Education, School of Chemistry and Materials Science, Shanxi Normal University, Linfen, 041004, China.
Research Institute of Materials Science, Shanxi Normal University, Linfen, 041004, China.
Nanoscale Res Lett. 2018 Jan 17;13(1):24. doi: 10.1186/s11671-018-2441-5.
Recent theoretical studies indicated that the Curie temperature of perovskite manganite thin films can be increased by more than an order of magnitude by applying appropriate interfacial strain to control orbital ordering. In this work, we demonstrate that the regular intercalation of BaTiO layers between LaSrMnO layers effectively enhances ferromagnetic order and increases the Curie temperature of LaSrMnO/BaTiO superlattices. The preferential orbital occupancy of e(x -y ) in LaSrMnO layers induced by the tensile strain of BaTiO layers is identified by X-ray linear dichroism measurements. Our results reveal that controlling orbital ordering can effectively improve the Curie temperature of LaSrMnO films and that in-plane orbital occupancy is beneficial to the double exchange ferromagnetic coupling of thin-film samples. These findings create new opportunities for the design and control of magnetism in artificial structures and pave the way to a variety of novel magnetoelectronic applications that operate far above room temperature.
最近的理论研究表明，通过施加适当的界面应变来控制轨道有序化，钙钛矿锰氧化物薄膜的居里温度可以提高一个数量级以上。在这项工作中，我们证明了在LaSrMnO层之间规则插入BaTiO层能有效增强铁磁序，并提高LaSrMnO/BaTiO超晶格的居里温度。通过X射线线性二色性测量确定了由BaTiO层的拉伸应变诱导的LaSrMnO层中e(x² - y²)的优先轨道占据。我们的结果表明，控制轨道有序化可以有效提高LaSrMnO薄膜的居里温度，并且面内轨道占据有利于薄膜样品的双交换铁磁耦合。这些发现为人工结构中磁性的设计和控制创造了新机会，并为在远高于室温下运行的各种新型磁电子应用铺平了道路。
