Regensburg 2019 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 41: Magnetic Textures: Statics and Imaging II

MA 41.13: Vortrag

Donnerstag, 4. April 2019, 12:45–13:00, H37

Nucleation process of the low-temperature skyrmion phase in Cu₂OSeO₃. — •Denis Mettus, Marco Halder, Alfonso Chacon, Andreas Bauer, and Christian Pfleiderer — Physik Department, Technische Universität München, Garching, Germany

Magnetic materials can host topologically non-trivial spin textures called skyrmions, which are an object of interest in recent years. For bulk chiral magnets with cubic lattice symmetry, it was believed that a skyrmion phase exists near the helimagnetic to paramagnetic transition, which is stabilized by thermal fluctuations.

Recently, a second skyrmion phase in Cu₂OSeO₃ has been identified at low temperatures (LTS), accompanied by a tilted conical phase. The new skyrmion phase is thermodynamically disconnected from the well-known high-temperature phase (HTS) and has a different stabilization mechanism given by cubic magnetocrystalline anisotropy terms.

We report a study of the nucleation process of the LTS. We present first order reversal magnetization data revealing that the nucleation of the LTS occurs by virtue of the tilted conical phase. We consider in addition the effects of magnetic field cycling on the magnetization and ac susceptibility for single crystal Cu₂OSeO₃ sample. The analysis of the susceptibility data allows us to identify the changes in the different phases concentrations with the varying parameters of a magnetic field cycling, which helps to understand the process of the phase nucleation.