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arXiv · 2306.12648

Discovery of antiferromagnetic chiral helical ordered state in trigonal GdNi$_3$Ga$_9$

Shota Nakamura·Takeshi Matsumura·Kazuma Ohashi·Hiroto Suzuki·Mitsuru Tsukagoshi·Kenshin Kurauchi·Hironori Nakao·Shigeo Ohara
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Abstract

We have performed magnetic susceptibility, magnetization, and specific heat measurements on a chiral magnet GdNi$_3$Ga$_9$, belonging to the trigonal space group $R32$ (\#155). A magnetic phase transition takes place at $T_{\rm N}$ = 19.5 K. By applying a magnetic field along the $a$ axis at 2 K, the magnetization curve exhibits two jumps at $\sim$ 3 kOe and = 45 kOe. To determine the magnetic structure, we performed a resonant X-ray diffraction experiment by utilizing a circularly polarized beam. It is shown that a long-period antiferromagnetic (AFM) helical order is realized at zero field. The Gd spins in the honeycomb layer are coupled in an antiferromagnetic manner in the $c$ plane and rotate with a propagation vector $q$ = (0, 0, 1.485). The period of the helix is 66.7 unit cells ($\sim 180$~nm). In magnetic fields above 3~kOe applied perpendicular to the helical $c$ axis, the AFM helical order changes to an AFM order with $q$ = (0, 0, 1.5).

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Shota Nakamura, Takeshi Matsumura, Kazuma Ohashi, Hiroto Suzuki, Mitsuru Tsukagoshi, Kenshin Kurauchi, Hironori Nakao, Shigeo Ohara. 2023-06-22. Discovery of antiferromagnetic chiral helical ordered state in trigonal GdNi$_3$Ga$_9$. https://doi.org/10.1103/physrevb.108.104422

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