近日，清华大学宋成小组报道了通过晶体对称对CrSb中交变磁序的操控。相关论文发表在2025年2月12日出版的《自然》杂志上。

据悉，晶体对称指导凝聚态物质的发展。连接磁性亚晶格的独特晶体对称性，不仅使变磁性区别于铁磁性和常规反铁磁性，而且使其结合了铁磁性和反铁磁性的优点。交替磁序本质上是一种磁晶序，由磁序矢量和晶体对称性决定。先前的实验研究主要集中在通过调整nsamel矢量的方向来控制电磁对称。然而，对晶体对称的操纵仍然具有挑战性，这对操控交替磁序有很大的希望。

该团队通过晶体对称实现了对锑化铬（CrSb）薄膜中交替磁序的操控。Dzyaloshinskii-Moriya矢量与磁空间对称之间的锁定，有助于从共线nsamel矢量到倾斜矢量重建交变磁序。它在交流磁体中产生室温自发异常霍尔效应。电流诱导自旋极化与Dzyaloshinskii-Moriya矢量之间的相对方向，决定了交变顺序的切换模式，即CrSb(1100)/Pt中的场辅助模式为平行模式，W/CrSb（1120）中的无场模式为非平行模式。

Dzyaloshinskii-Moriya矢量在场辅助模式下诱导非对称能量势垒，在无场模式下产生非对称驱动力。后者是由交替磁体中新兴的Dzyaloshinskii-Moriya扭矩保证的。重建晶体的对称性为磁变序的操控增加了新的思路。它不仅支撑了磁记忆和纳米振荡器技术，而且还激发了电磁学和其他研究课题之间的交叉研究。

附：英文原文

Title: Manipulation of the altermagnetic order in CrSb via crystal symmetry

Author: Zhou, Zhiyuan, Cheng, Xingkai, Hu, Mengli, Chu, Ruiyue, Bai, Hua, Han, Lei, Liu, Junwei, Pan, Feng, Song, Cheng

Issue&Volume: 2025-02-12

Abstract: Crystal symmetry guides the development of condensed matter. The unique crystal symmetry connecting magnetic sublattices not only distinguishes altermagnetism1,2,3,4,5,6 from ferromagnetism and conventional antiferromagnetism but also enables it to combine the advantages of ferromagnetism and antiferromagnetism4,5. Altermagnetic order is essentially a magnetic crystal order7, determined by the magnetic-order (Néel) vector and crystal symmetry. Previous experimental studies have concentrated on manipulating the altermagnetic symmetry by tuning the Néel vector orientations8,9,10,11,12. However, manipulation of the crystal symmetry, which holds great promise for manipulating the altermagnetic order, remains challenging. Here we realize the manipulation of altermagnetic order in chromium antimonide (CrSb) films via crystal symmetry. The locking between the Dzyaloshinskii–Moriya vector and the magnetic space symmetry helps to reconstruct the altermagnetic order, from a collinear Néel vector to a canted one. It generates a room-temperature spontaneous anomalous Hall effect in an altermagnet. The relative direction between the current-induced spin polarization and the Dzyaloshinskii–Moriya vector determines the switching modes of altermagnetic order, that is, parallel for the field-assisted mode in CrSb（1100）/Pt and non-parallel for the field-free mode in W/CrSb（1120）. The Dzyaloshinskii–Moriya vector induces an asymmetric energy barrier in the field-assisted mode and generates an asymmetric driving force in the field-free mode. In particular, the latter is guaranteed by the emerging Dzyaloshinskii–Moriya torque in altermagnets. Reconstructing crystal symmetry adds a new twist to the manipulation of altermagnetic order. It not only underpins the magnetic-memory and nano-oscillator technology4,5 but also inspires crossover studies between altermagnetism and other research topics.

DOI: 10.1038/s41586-024-08436-3

Source: https://www.nature.com/articles/s41586-024-08436-3