Anisotropic magnetic domain in magnetic Weyl semimetal candidate Co₃Sn₂S₂

We use small-angle neutron scattering (SANS) to study the formation and field evolution of the magnetic domains in the magnetic Weyl semimetal candidate Co₃Sn₂S₂. For zero-field-cooling (ZFC) measurement at 145 K (below T_c ≈177 K), we observe highly anisotropic magnetic scattering signals best described by a 2d x 1d product form. We determine the out-of-plane (1d) correlation length ξ_c=8.2(2.5) μm and observe the large-q tails of the in-plane (2d) magnetic scattering indicating a lower cut-off of the in-plane correlation length ξ_a ≥0.25 μm. The magnetic domains are aligned upon applying a field of 0.1 T and form an isotropic structure when the field is reduced back to zero. Our work compliments the previously reported magneto-optic Kerr microscopy [1] and give the first characterization of the domain structure along the out-of-plane direction in Co₃Sn₂S₂. We also conduct detailed bulk magnetization measurements and observe a nucleation temperature T_n=135(5) K and the influence of inhomogeneity on the magnetization curves.

[1] Lee, Changmin, et al. "Observation of a phase transition within the domain walls of ferromagnetic Co3Sn2S2." Nature Communications 13.1 (2022): 1-6.