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arXiv · 2003.03719

Field-induced spin reorientation in the antiferromagnetic Dirac material EuMnBi$_2$ revealed by neutron and resonant x-ray diffraction

H. Masuda·H. Sakai·H. Takahashi·Y. Yamasaki·A. Nakao·T. Moyoshi·H. Nakao·Y. Murakami·T. Arima·S. Ishiwata
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Abstract

Field-dependent magnetic structure of a layered Dirac material EuMnBi$_2$ was investigated in detail by the single crystal neutron diffraction and the resonant x-ray magnetic diffraction techniques. On the basis of the reflection conditions in the antiferromagnetic phase at zero field, the Eu moments were found to be ordered ferromagnetically within the $ab$ plane and stacked antiferromagnetically along the $c$ axis in the sequence of up-up-down-down. Upon the spin-flop transition under the magnetic field parallel to the $c$ axis, the Eu moments are reoriented from the $c$ to the $a$ or $b$ directions forming two kinds of spin-flop domains, whereas the antiferromagnetic structure of the Mn sublattice remains intact as revealed by the quantitative analysis of the change in the neutron diffraction intensities. The present study provides a concrete basis to discuss the dominant role of the Eu sublattice on the enhanced two-dimensionality of the Dirac fermion transport in EuMnBi$_2$.

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H. Masuda, H. Sakai, H. Takahashi, Y. Yamasaki, A. Nakao, T. Moyoshi, H. Nakao, Y. Murakami, T. Arima, S. Ishiwata. 2020-03-08. Field-induced spin reorientation in the antiferromagnetic Dirac material EuMnBi$_2$ revealed by neutron and resonant x-ray diffraction. https://doi.org/10.1103/physrevb.101.174411

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