Tunable gigahertz dynamics of low-temperature skyrmion lattice in a chiral magnet

Oscar Lee, Jan Sahliger, Aisha Aqeel, Safe Khan, Shinichiro Seki, Hidekazu Kurebayashi, Christian H. Back

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

Recently, it has been shown that the chiral magnetic insulator Cu2OSeO3 hosts skyrmions in two separated pockets in temperature and magnetic field phase space. It has also been shown that the predominant stabilization mechanism for the low-temperature skyrmion (LTS) phase is via the crystalline anisotropy, opposed to temperature fluctuations that stabilize the well-established high-temperature skyrmion (HTS) phase. Here, we report on a detailed study of LTS generation by field cycling, probed by GHz spin dynamics in Cu2OSeO3. LTSs are populated via a field cycling protocol with the static magnetic field applied parallel to the 100 crystalline direction of plate and cuboid-shaped bulk crystals. By analyzing temperature-dependent broadband spectroscopy data, clear evidence of LTS excitations with clockwise (CW), counterclockwise (CCW), and breathing mode (BR) character at temperatures below T = 40 K are shown. We find that the mode intensities can be tuned with the number of field-cycles below the saturation field. By tracking the resonance frequencies, we are able to map out the field-cycle-generated LTS phase diagram, from which we conclude that the LTS phase is distinctly separated from the high-temperature counterpart. We also study the mode hybridization between the dark CW and the BR modes as a function of temperature. By using two Cu2OSeO3 crystals with different shapes and therefore different demagnetization factors, together with numerical calculations, we unambiguously show that the magnetocrystalline anisotropy plays a central role for the mode hybridization.

Original languageEnglish
Article number095801
JournalJournal of Physics Condensed Matter
Volume34
Issue number9
DOIs
StatePublished - 2 Mar 2022

Keywords

  • lattice dynamics
  • magnetic order
  • magnetism
  • magnetization dynamics
  • skyrmions

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