||関 真一郎 准教授
||Microwave spectroscopy in polar magnetic insulator VOSe2O5
||Inversion symmetry breaking in crystal structures can lead to unusual physical properties and nontrivial responses to external fields. In magnetic materials, inversion symmetry breaking allows for the existence of Dzyaloshinskii-Moriya (DM) interactions, which can lead to a variety of magnetic spin textures. In addition, a large photovoltaic effect has recently been observed in materials with broken space-inversion symmetry, depending on a quantum mechanical mechanism called the shift current, simply by irradiating visible light on the bulk crystals. From the above viewpoints, the development of magnetic materials with broken inversion symmetry is very valuable for applications.
In this presentation, we describe experimental observations of the microwave response of VOSe2O5, a magnetic material with broken space-inversion symmetry, which has been shown to exhibit helical magnetism under zero magnetic field due to the presence of DM interactions and an unusual magnetic structure called a Ne’el-type magnetic skyrmion at a certain condition[1,2].
In this research, we investigate the microwave response of such magnetic structures in detail. The presentation will begin with a general discussion of hellical magnetism, the magnetic structure in VOSe2O5, the setup of the present experiment, and finally the experimental results and future prospects.
 T. Kurumaji et al,. Phys. Rev. Lett. 119, 237201 (2017)
 T. Kurumaji et al,. J. Phys. Soc. Jpn. 90, 024705 (2021)