反铁电-铁电可逆相变调控、界面物理行为及电控反铁磁的同步辐射研究

As an emerging field in condensed matter physics, antiferromagnetic spintronics, which is promising for future memory devices, is developing rapidly. How to manipulate the antiferromagnetic order is playing a key role to realize the antiferromagnetic spintronic memory. Nowadays, strong magnetic field, strain, optical excitation and current are applied to induce the antiferromagnetic order switching. However, these approaches are technically difficult and complicated. Therefore, it is urgent to explore a new pathway to switch the antiferromagnetic order. .Our previous study has reveals the change of the antiferromagnetic axis orientation from in plane to out of plane during the antiferroelectric to ferroelectric phase transitions. It is well known that electric field is an efficient way to drive antiferroelectric to ferroelectric phase transitions. Motivated by this, we propose to use the electric field reversible control of antiferromagnetism at room temperature. In this study, based on the growth of high quality La-BiFeO3 epitaxial thin films, we will explore the novel physical properties in the antiferroelectric/ferroelectric phase boundary. Then, electric field will be applied to reversibly drive the antiferroelectric-ferroelectric phase transitions, in order to realize the reversible switching of antiferromagnetism. The implementation of this project will promote the realization of antiferromagnetic spintronic memory device application.

反铁磁自旋电子学这一凝聚态物理的新兴领域正在步入快速发展阶段，在开发新型信息存储器件方面有着广泛的应用前景。对于反铁磁序的调控已成为推动其应用进程的关键科学问题。目前的研究集中在利用强磁场、应变、光激发以及电流驱动等方式实现反铁磁序的操控。然而，这些方法虽然从原理上实现了反铁磁的信息存储功能，但技术层面都各有难言之隐。因此，探索有效调控反铁磁序的新方法已迫在眉睫。我们的前期研究发现室温多铁性材料La掺杂BiFeO3中反铁电-铁电的相变引起了反铁磁轴的方向由面内转向了面外。另外，电场是调控反铁电-铁电相变的有效途径。受此启示，我们提出室温下实现电场对反铁磁性的有效往复调控。本项目拟在生长高质量薄膜的基础上，探究反铁电/铁电界面的新颖物理特性，进而通过施加电场实现对反铁电-铁电相变的可逆调控，最终实现电场对反铁磁的可逆操控。本项目的顺利实施将推动反铁磁自旋电子存储器件的应用进程。

量子效应的物理极限使得摩尔定律正在走向终结。因此，迫切需要发展具有新结构、新物理的下一代信息存储材料与器件。多铁性材料中晶格、自旋、电荷等各种序参量的竞争和共存，对材料的行为调控是一种不同于传统半导体微电子学的全新方案，是后摩尔时代新型电子技术的重要前沿发展方向。本项目在生长高质量多铁性La-BiFeO3外延薄膜的基础上，探索了电场驱动反铁电-铁电的正交-菱方相变，考察了其界面物理行为，提供了室温电场调控反铁磁性的有效途径。在该项目的资助下，在Matter，Nanoscale，Materials Today Physics, Nano Energy, National Science Review，Physical Review B等期刊发表SCI论文20篇。研究成果有望促进高密度、低能耗反铁磁自旋电子器件的研发。