基于锂离子迁移的室温电场（无电流）对氧化物薄膜磁性能的调控

As a next-generation technology for magnetic storage applications, the electric field control of magnetic properties can weaken the Joule heat caused by the electric current and reduce power consumption. The applicant's previous researches found that the room temperature electric field (without electric current) can non-volatile control the magnetic properties by driving Mg2+, Al3+ and Li+ to migrate at the interface of the iron oxide film heterojunction, but the cycle reversibility is not good. This project intends to construct the oxide film heterojunction by using the positive and negative electrode materials of lithium ion battery, and study the room temperature electric field (without electric current) control of magnetic properties of the oxide solid films based on lithium ion migration. (1) This project intends to study the magnetic laws and mechanisms of film heterojunctions such as LiCoO2/C, LiNiO2/C, LiMn2O4/C and LiFe2O4/C; (2) This project intends to change the structure of the oxide film, the valence and magnetic moment of the ions by driving the lithium ions to reciprocate on the both sides of the oxide film heterojunction interface by the room temperature electric field (without electric current), such as LiCoO2/C, LiNiO2/C, LiMn2O4/C and LiFe2O4/C, to reach the purpose of non-volatile, reversible, cyclic control of the magnetic properties by electric field (without electric current), and reveal the mechanism of electric field (without electric current) control of magnetic properties. It is designed to provide a new choice for low-power electronics and spintronics.

作为下一代磁存储技术，电场调控磁性可消弱电流带来的焦耳热，降低功耗。申请人前期研究发现，室温电场（无电流）驱动Mg2+、Al3+、Li+在氧化铁薄膜异质结界面处迁移，可以非易失性调控磁性，但循环可逆性不好。本项目拟利用锂离子电池正极和负极材料构建氧化物薄膜异质结，研究基于锂离子迁移的室温电场（无电流）调控氧化物固态薄膜的磁性。（1）本项目拟研究LiCoO2/C、LiNiO2/C、LiMn2O4/C和LiFe2O4/C等薄膜异质结的磁性规律及机制；（2）本项目拟通过室温电场（无电流）驱动Li+在LiCoO2/C、LiNiO2/C、LiMn2O4/C和LiFe2O4/C等薄膜异质结界面两侧往复迁移的方式，来调控氧化物的结构、离子的价态和磁矩，达到电场（无电流）非易失性、可逆、循环调控薄膜磁性的目的,并揭示电场（无电流）调控磁性的机理。旨在提供一个可通向低功耗电子学和自旋电子学的新选择。

对电控磁性能进行了调研综述研究。由结构和成分不同的材料形成的界面具有与电荷和自旋相关联的可控性能。在电场或电压作用下，界面处的易迁移的离子会受到驱动而发生往复迁移，可能会导致由磁性材料和非磁性材料组成的异质结界面处的局域结构、离子价态和磁矩发生变化。这为调节薄膜材料的磁性能提供途径。本项目研究了基于电场驱动Li离子迁移的电场调控氧化物薄膜的磁性能，具体研究在常规的Li离子电池的阳极材料和阴极材料形成的异质结中实现电场调控磁性能，具体研究基于电场驱动Li离子迁移在氧化铁异质结中实现电场调控磁性能。本项目鉴于Li离子与H离子的相似性，依据基于电场驱动Li离子迁移的实验中获得的数据，延伸研究了基于电场驱动H离子迁移的电调控磁性能，并逐步涉及到电流对磁性能的调控，以及理论分析异质结极化界面的形成机制，以期开始逐步深入理解界面发生的事情。