CEMES , Université de Toulouse, CNRS , 29 rue Jeanne-Marvig , 31055 Toulouse , France.
Université de Strasbourg, CNRS, IPCMS, UMR 7504 , 67000 Strasbourg , France.
ACS Appl Mater Interfaces. 2019 Sep 18;11(37):34399-34407. doi: 10.1021/acsami.9b08906. Epub 2019 Sep 10.
Based on first-principles calculations, we predict the polarization control of the interfacial magnetic phase and a giant electronically driven magnetoelectric coupling (MEC) in Co/PbZrTiO (PZT)(001). The effect of Co oxidation at the interface shared with (Zr,Ti)O-terminated PZT is evidenced. The magnetic phase of the oxidized Co interface layer is electrically switched from the ferromagnetic to the antiferromagnetic state by reversing the PZT polarization from upward to downward, respectively. A comparative study between oxidized and unoxidized Co/PZT interfaces shows that in oxidized Co/PZT bilayers, the variation of the interface spin moment upon polarization reversal exceeds that of unoxidized Co/PZT bilayers by about 1 order of magnitude. We define a surface MEC constant α taking into account the polarization dependence of both the spin and orbital moments. In unoxidized Co/PZT bilayers, we obtain α ≈ 2 × 10 G cm V, while a giant surface coupling α ≈ 12 × 10 G cm V is found in the case of oxidized Co/PZT. We demonstrate that the polarization control of the magnetocrystalline anisotropy via spin-orbit coupling is not only effective at the interface but it extends to the Co film despite the interface origin of the MEC. This study shows that tailoring the nature of atomic bonding and electron occupancies allows for improving the performance of functional interfaces, enabling an efficient electric field control of spin-orbit interactions. Moreover, the nonlocal character of this effect holds promising perspectives for the application of electronically driven interface MEC in spin-orbitronic devices.
基于第一性原理计算，我们预测了界面磁性相和巨大电驱动磁电耦合（MEC）在 Co/PbZrTiO（PZT）（001）中的极化控制。证据表明 Co 在与（Zr，Ti）O 终止的 PZT 共享界面处发生了氧化。通过分别将 PZT 极化从向上反转到向下，氧化的 Co 界面层的磁相从铁磁态电切换到反铁磁态。对氧化和未氧化的 Co/PZT 界面的比较研究表明，在氧化的 Co/PZT 双层中，极化反转时界面自旋矩的变化比未氧化的 Co/PZT 双层大约大 1 个数量级。我们定义了一个表面 MEC 常数α，该常数考虑了自旋和轨道矩的极化依赖性。在未氧化的 Co/PZT 双层中，我们得到α≈2×10 G cm V，而在氧化的 Co/PZT 情况下，发现了巨大的表面耦合α≈12×10 G cm V。我们证明了通过自旋轨道耦合对磁各向异性的极化控制不仅在界面上有效，而且尽管 MEC 起源于界面，但它延伸到 Co 薄膜。这项研究表明，通过调整原子键合和电子占据的性质，可以改善功能界面的性能，从而实现对自旋轨道相互作用的有效电场控制。此外，这种效应的非局域特性为电子驱动界面 MEC 在自旋轨道电子器件中的应用提供了有前景的前景。
