Magnetotransport in Fe-intercalated \textit{T}S$_2$: the comparison between \textit{T} = Ti and Ta

Abstract

Sharp magnetization switching and large magnetoresistance were previously discovered in single crystals of 2H-FexTaS2 and attributed to the Fe superstructure and its defects. We report similar sharp switching in 1T-FexTiS2 (0.086 ≤ x ≤0.703) and the discovery of large magnetoresistance. The switching field Hs and magnetoresistance are similar to 2H-FexTaS2, with a larger than expected bowtie magnetoresistance and a sharp hysteresis loop. Despite previous reports, electron diffraction shows only the √ 3× √ 3 superstructure in 1T-FexTiS2. The Curie and Weiss temperatures remain roughly constant below x ∼ 1/3 before monotonically increasing for higher x. By contrast, the switching field and magnetoresistance reach a maximum where defects in the superstructure exist, approach a minimum near perfect superstructures, and remain constant above x ∼ 0.4. Additionally, an increase in Hs with annealing time is reported. Glassy behavior is shown to coexist within the ferromagnetic state in 1T-FexTiS2 for compositions between 0.1 and 0.703. A simple model captures the essential phenomenology and explains most similarities and differences between 1T-FexTiS2 and 2H-FexTaS2, and provides insights into other magnetically intercalated transition metal dichalcogenides.