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arXiv · 1909.08179

Augmented Magnetic Octupole in Kagome Antiferromagnets Detectable via X-ray Magnetic Circular Dichroism

Yuichi Yamasaki·Hironori Nakao·Taka-hisa Arima
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Abstract

The magneto-optical Kerr effect (MOKE) has recently been discovered in antiferromagnetic Kagome lattice Mn3Sn. Since the compound exhibits a coplanar $120^\circ$ antiferromagnetic (AFM) order, the magnetic moments cancel each other, and the net magnetization is almost zero. However, the MOKE is allowed due to the lack of the time-reversal symmetry (TRS) of the AFM order. X-ray magnetic circular dichroism (XMCD) can detect a difference in up and down the spin density of states (DOS), and thus XMCD originating from the spin operator, the so-called Sz term, should be negligibly small as well as the net magnetization. Nonetheless, we show that XMCD originating from the magnetic dipole operator, the so-called Tz term, should remain uncancelled in the AFM with the broken TRS. Moreover, we clarify that there is a strong link between the Tz term and the augmented magnetic octupole (AMO), which suggests that XMCD can be an effective approach for analyzing multipole moments in antiferromagnets.

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Yuichi Yamasaki, Hironori Nakao, Taka-hisa Arima. 2019-09-18. Augmented Magnetic Octupole in Kagome Antiferromagnets Detectable via X-ray Magnetic Circular Dichroism. https://doi.org/10.7566/jpsj.89.083703

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