RKKY Ferromagnetism with Ising-Like Spin States in Intercalated Fe(1/4)TaS(2)

Abstract

We investigated the magnetic nature of Fe1/4TaS2 using x-ray absorption spectroscopy, photoemission spectroscopy, and first principles band calculations. The results show a large unquenched orbital magnetic moment (similar to 1.0 mu(B)/Fe) at intercalated Fe sites, resulting in a gigantic magnetic anisotropy (H-A similar or equal to 60 T). The magnetic coupling is well understood in terms of the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction, suggesting a novel RKKY ferromagnet with Ising-type spin states. We also found that this indirect exchange coupling between the neighboring Fe spins is ferromagnetic and maximized at the Fe-Fe distance of 2 x 2 superstructure.