||小濱 芳允 准教授
||Quantum oscillations in a centrosymmetric skyrmion-hosting material
||Magnetic skyrmions, topologically stable spin swirls with a particle-like character, have been intensively investigated as a candidate for high-density information bits. Previously, skyrmions have been discovered in non-centrosymmetric materials. This lack of symmetry causes Dzyaloshinskii-Moriya (DM) interaction, which favors a twisted spin texture, and have been thought to be essential for the skyrmion formation. However, recent theories predicted that skyrmions can be stabilized even in centrosymmetric materials. Indeed, very recently, skyrmions have been observed in several centrosymmetric Gd compounds[1,2].
GdRu2Si2 is one of such centrosymmetric skyrmion-hosting materials. Its magnetic behavior is well explained by the model where the magnetism is mediated by itinerant electrons, though the first principle calculation predicted that the itinerant-electron-mediated interaction in this material is negligibly small. Thus, the actual mechanism of skyrmion formation is still under debate.
In this research, to observe quantum oscillations, we performed magnetic-torque measurements. Based on the observed quantum oscillations, I will discuss the electronic properties and the relationship to the magnetism in GdRu2Si2.
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 N. D. Khanh, et al., Nat. Nanotechnol. 15, 444 (2020).
 S. Hayami, et al., Phys. Rev. B 95, 224424 (2017).
 T. Nomoto, et al., Phys. Rev. Lett. 125, 117204 (2020).