Topological antiferromagnetic spin valve

拓扑反铁磁自旋阀

• 批准号: 21F21045
• 负责人: 中辻 知
• 金额: $ 1.54万
• 依托单位: The University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for JSPS Fellows
• 财政年份: 2021
• 资助国家: 日本
• 起止时间: 2021-04-28 至 2023-03-31
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-21F21045/
• 关键词: antiferromagnets; TMR; nonvolatile memory

In FM/NM/FM trilayers (FM: ferromagnet, NM: nonmagnet), the change of relative orientation between the two FM moments could lead to varying opposition to the tunneling current flow: this tunneling magnetoresistance (TMR) is proportional to the spin polarization of FMs as is characterized by the Julliere’s model, and thus it is not usually seen in antiferromagnets with negligible spin polarization. Here, we demonstrate the existence of antiferromagnetic TMR in a magnetic octupole valve Mn3Sn/MgO/Mn3Sn, supported by the theory. Remarkably, although the spin polarization rate is three orders smaller than that of Fe, Mn3Sn/MgO/Mn3Sn shows 5 times larger TMR than Fe/MgO/Mn3S. This emphasizes the dominant role of octupole polarization, instead of spin polarization.

在FM/NM/FM三层（FM：铁磁体，NM：非磁体）中，两个FM矩之间的相对取向变化会导致隧道电流的相反方向变化：这种隧道磁电阻（TMR）与FM的自旋极化成正比，这是Julliere模型的特征，因此在自旋极化可忽略的反铁磁体中通常不会出现。在这里，我们证明了在磁性八极阀Mn3Sn/MgO/Mn3Sn中存在反铁磁TMR，并得到了理论支持。值得注意的是，虽然Mn3Sn/MgO/Mn3Sn的自旋极化率比Fe小3个数量级，但其TMR却是Fe/MgO/Mn3S的5倍。这强调了八极极化的主导作用，而不是自旋极化。