Tsuei-Shin Wu1*, Yen-Chen Tsui1, Syu-You Guan1, Paul Malinowski2, Jiun-Haw Chu2, Tien-Ming Chuang1
1 Institute of Physics, Academia Sinica, Taipei, Taiwan
2 Department of Physics, University of Washington, Seattle, WA, USA
* Current address: Institute of Applied Physics, Technische Universität Dresden, Dresden, Germany
Ferromagnetic Weyl semimetal Co3Sn2S2, within which Co atoms form a quasi-2D Kagomé lattice, has attracted great attention because novel phenomena such as quantum anomalous Hall effect can emerge as the results of the interplay between topology and magnetism. While the existence of Weyl points and Fermi arcs have been realized in the ferromagnetic state at low temperature [1-2], an anomalous magnetic phase (A-phase) revealed by low-field magnetization, AC susceptibility [3] and transport [4] measurements slightly below its Curie temperature remain unsolved. Skyrmion phase [3], spin glass [5], co-existence of out-of-plane ferromagnetic and in-plane antiferromagnetic order [6], and a 2D phase transition within the domain walls [7] have been proposed. Here, we conducted comprehensive magnetic imaging study on Co3Sn2S2 single crystals by using variable temperature magnetic force microscopy (MFM) across the A-phase. Our temperature dependent and magnetic field dependent MFM images demonstrate the important role of magnetic bubble domain formation and the magnetic domain wall motion in the A-phase, consistent with a recent study by Lorentz microscopy [8].
References
[1] Liu et al., Science 365, 1282–1285 (2019).
[2] Morali et al., Science 365, 1286–1291 (2019).
[3] Kassem et al., PRB 96, 014429 (2017).
[4] Lachman et al., Nat. Commun. 11, 560 (2020).
[5] Lachman et al., Nature Communications 11, 560 (2020).
[6] Guguchia et al., Nature Communications 11, 559 (2020).
[7] Lee et al., Nat Commun 13, 3000 (2022).
[8] Sugawara et al., Physical Review Materials 3, 104421 (2019).