*

The layered transition metal dichalcogenide TaS₂ exhibits a broad range of phases including CDW states and superconductivity [1]; the polymorph 1T-TaS₂ has even been predicted to host a spin liquid [2]. Also of interest is the doping of such materials with metallic ions. In TaS₂ the intercalation of Iron between layers stabilizes ferromagnetic order. The magnetic properties vary drastically with the amount of intercalant, x [3]. For example, for x=0.33 chiral superlattice structures form [4]. Here we employ scanning Magneto-Optical Kerr Effect (MOKE) microscopy to image the onset of magnetic order and in some instances optical birefringence in compounds with intercalation from x=0.26 to 0.33. In the x=0.33 compound we report a sharp structural phase transition coincident with the magnetic transition and image the resulting domains on a 10-μm scale.

[1] J.A. Wilson & A.D. Yoffe, Advances in Physics 18:73, 193-335, (1969)
[2] K. T. Law, Patrick A. Lee, PNAS 114 (27) 6996-7000; (2017)
[3] M. Eibshutz et al., Journal of Applied Physics 52, 2098 (1981)
[4] Y. Horibe et al., Color Theorems, Journal of the American Chemical Society (2014)