Berlin 2018 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 37: Skyrmions II (joint session MA/TT/KFM)
TT 37.5: Talk
Tuesday, March 13, 2018, 10:30–10:45, EB 301
Effects of Magnetocrystalline Anisotropy on the Triangular to Square Lattice Transformation of Skyrmions — •Markus Preißinger1, Dieter Ehlers1, Kosuke Karube2, István Kézsmárki1, Hans-Albrecht Krug von Nidda1, Bertalan Szigeti3, Yusuke Tokunaga2, Yasujiro Taguchi2, Yoshinori Tokura2, and Vladimier Tsurkan1 — 1Experimentalphysik V, EKM, Universität Augsburg, 86135 Augsburg — 2RIKEN Centre for Emergent Matter Science (CEMS), Wako 351-0198, Japan — 3Department of Physics, Budapest University of Technology and Economics, 1111 Budapest, Hungary
The β-manganese-type alloy Co8Zn8Mn4 exhibits a helical state below the Curie-temperature Tc ≈ 300 K 1. Below the phase transition, between 300 K and 284 K, an equilibrium skyrmion lattice state occurs in weak magnetic fields in the range of 400 Oe. This state can be quenched down to lower temperatures by rapid field cooling. Below 150 K the metastable triangular skyrmion lattice transforms into a square lattice 2. The magnetocrystalline anisotropy in the ferromagnetic phase was determined by ferromagnetic resonance measurements. We discuss its impact on the phase transition between the two types of skyrmion lattices. On cooling, the increasing cubic anisotropy constant K1 seems to drive the phase transition of the skyrmion lattice between 150 K and 40 K. The temperature dependence of the corresponding critical fields turns out to be correlated to the anisotropy constant K1.
1 T. Hori et al., J. Magn. Magn. Mater. 310, 1820–1822 (2007).
2 K. Karube et al., Nature Materials 15, 1237–1243 (2016).