"Large magneto-optical Kerr effect and imaging of magnetic octupole domains in an antiferromagnetic metal"

Tomoya Higo: Huiyuan Man, Daniel B. Gopman, Liang Wu, Takashi Koretsune, Olaf M. J. van ’t Erve, Yury P. Kabanov, Dylan Rees , Yufan Li, Michi-To Suzuki, Shreyas Patankar, Muhammad Ikhlas, C. L. Chien, Ryotaro Arita, Robert D. Shull; Nature Photonics, 01/26/18.

Additional Authors: Huiyuan Man, Daniel B. Gopman, Liang Wu, Takashi Koretsune, Olaf M. J. van ’t Erve, Yury P. Kabanov, Dylan Rees , Yufan Li, Michi-To Suzuki, Shreyas Patankar, Muhammad Ikhlas, C. L. Chien, Ryotaro Arita, Robert D. Shull

Abstract:

The magneto-optical Kerr effect (MOKE) has been intensively studied in a variety of ferro- and ferrimagnetic materials as a powerful probe for electronic and magnetic properties1,2,3 and for magneto-optical technologies4. The MOKE can be additionally useful for the investigation of the antiferromagnetic (AF) state, although thus far limited to insulators5,6,7,8,9. Here, we report the first observation of the MOKE in an AF metal. In particular, we find that the non-collinear AF metal Mn3Sn (ref. 10) exhibits a large zero-field Kerr rotation angle of 20 mdeg at room temperature, comparable to ferromagnetic metals. Our first-principles calculations clarify that ferroic ordering of magnetic octupoles11 produces a large MOKE even in its fully compensated AF state. This large MOKE further allows imaging of the magnetic octupole domains and their reversal. The observation of a large MOKE in an AF metal will open new avenues for the study of domain dynamics as well as spintronics using antiferromagnets12,13,14,15,16.