Large Orbital Magnetic Moment and Strong Perpendicular Magnetic Anisotropy in Heavily Intercalated FexTiS2

Abstract

Titanium disulfide TiS2, which is a member of layered transition-metal dichalcogenides with the 1T-CdI2-type crystal structure, is known to exhibit a wide variety of magnetism through intercalating various kinds of transition-metal atoms of different concentrations. Among them, Fe-intercalated titanium disulfide FexTiS2 is known to be ferromagnetic with strong perpendicular magnetic anisotropy (PMA) and large coercive fields (Hc). In order to study the microscopic origin of the magnetism of this compound, we have performed X-ray absorption spectroscopy (XAS) and X-ray magnetic circular dichroism (XMCD) measurements on single crystals of heavily intercalated FexTiS2 (x ∼ 0.5). The grown single crystals showed a strong PMA with a large Hc of μ0Hc ≃ 1.0 T. XAS and XMCD spectra showed that Fe is fully in the valence states of 2+ and that Ti is in an itinerant electronic state, indicating electron transfer from the intercalated Fe atoms to the host TiS2 bands. The Fe 2+ ions were shown to have a large orbital magnetic moment of ≃ 0.59 μB/Fe, to which, combined with the spin-orbit interaction and the trigonal crystal field, we attribute the strong magnetic anisotropy of FexTiS2.