Broadband microwave spectroscopy has been performed on single-crystalline GaV4S8, which exhibits a complex magnetic phase diagram including cycloidal, N\'eel-type skyrmion lattice, as well as field-polarized ferromagnetic phases below 13 K. At zero and small magnetic fields two collective modes are found at 5 and 15 GHz, which are characteristic of the cycloidal state in this easy-axis magnet. In finite fields, entering the skyrmion lattice phase, the spectrum transforms into a multi-mode pattern with absorption peaks near 4, 8, and 15 GHz. The spin excitation spectra in GaV4S8 and their field dependencies are found to be in close relation to those observed in materials with Bloch-type skyrmions. Distinct differences arise from the strong uniaxial magnetic anisotropy of GaV4S8 not present in so-far known skyrmion hosts.
@article{arxiv.1512.02391,
title = {Magnetic Excitations in the Multiferroic N\'eel-type Skyrmion Host GaV$_4$S$_8$},
author = {Dieter Ehlers and Ioannis Stasinopoulos and Vladimir Tsurkan and Hans-Albrecht Krug von Nidda and Titusz Fehér and Andrey Leonov and István Kézsmárki and Dirk Grundler and Alois Loidl},
journal= {arXiv preprint arXiv:1512.02391},
year = {2016}
}