Giant Strain Control of Antiferromagnetic Moment in Metallic FeMn by Tuning Exchange Spring Structure
Giant Strain Control of Antiferromagnetic Moment in Metallic FeMn by Tuning Exchange Spring Structure
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通过调节交换弹簧结构控制金属 FeMn 中的反铁磁矩的巨应变
DOI：
10.1002/adfm.201909708
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发表时间：
2020-02-16
影响因子：
19
通讯作者：
Yu, Guanghua
中科院分区：
文献类型：
--
作者：
Feng, Chun;Li, Yukun;Yu, Guanghua
对反铁磁体中反铁磁矩的控制是发展反铁磁自旋电子器件的关键问题。晶格应变是调制反铁磁磁矩的有效策略，传统上是基于AFM的直接晶体剪裁。提出了一种通过控制原子力显微镜中的交换弹簧来实现反铁磁力矩应变调谐的新方法，该方法适用于其它常规原子力显微镜材料。具体地，使用TiNi（Nb）形状记忆合金（SMA）作为Ta/NiFe/FeMn多层膜的基底。通过热驱动的逆马氏体相变中的SMA，一个显着的应变1.3%被转移到膜中，这触发了一个明显的磁矩旋转NiFe的近90度的膜平面，导致在随后的旋转的Neel矢量的FeMn由于界面交换相互作用。反过来，FeMn的反铁磁力矩是可剪裁的通过调整交换弹簧。同时，由于反铁磁矩的扭曲，交换偏置场被显著调谐，最大变化为350%，这有利于应变辅助磁化反转，用于开发逻辑存储器件。这些发现提供了一种替代策略，以推进基于AFM的存储器的温度驱动的应变工程的发展。
Manipulation of the antiferromagnetic moment in antiferromagnets (AFMs) is a crucial issue for developing AFM-based spintronic devices. Lattice strain is an effective strategy to modulate the antiferromagnetic moment and is traditionally based on a direct crystalline tailoring of AFMs. A novel method for strain tuning the antiferromagnetic moment by controlling the exchange spring in the AFM, which is applicable to other conventional AFM materials, is reported. Specifically, a TiNi(Nb) shape memory alloy (SMA) is used as the substrate of Ta/NiFe/FeMn multilayers. By thermally driven inverse martensitic phase transformation in the SMA, a significant strain of 1.3% is transferred into the film, which toggles a noticeable magnetic moment rotation of NiFe by nearly 90 degrees in the film plane, resulting in a consequent twirling of the Neel vector of FeMn due to interfacial exchange interaction. In turn, the antiferromagnetic moment of FeMn is tailorable by tuning the exchange spring. Simultaneously, the exchange bias field is tuned significantly with a maximal variation of 350% due to the twist of the antiferromagnetic moment, which facilitates strain-assisted magnetization reversal for developing a logic memory device. These findings provide an alternative strategy to advance the development of an AFM-based memorizer by temperature-driven strain engineering.