Effects of Iron Doping on the Physical Properties of Quaternary Ferromagnetic Sulfide: Ba 2 Fe 0.6 V 1.4 S 6

The mixed-metal sulfide compound with the formula Ba Fe V S was successfully synthesized via solid-state reaction. Ba Fe V S has a quasi-one-dimensional structure and crystallizes in the hexagonal space group P6 /mmc. The structure is composed of face-sharing anion octahedron [MS ] (M = V or Fe) units to construct infinite chains along the c axis, in which the Fe atoms randomly occupy the V sites. The Ba ions reside between adjacent chains. Magnetic susceptibility measurements reveal a transition between paramagnetism and ferromagnetism around 25 K. The small polaron hopping (SPH) conduction behavior has been observed in the higher temperature region (75-300 K), while in the lower temperature region (25-74 K), the resistivity features a variable range hopping mechanism (VRH). The analysis of density of states indicates that Fe-3d and S-3p states mainly dominate the valence band maximum, while Fe-3d states contribute significantly to the magnetic susceptibility.