Crystallographic and M？ssbauer Studies for Ni0.9957Fe0.01Ga2S4

Ni0.9957Fe0.0₁Ga₂S₄ was fabricated by using a solid-state method with high-purity elements of Fe, Ni, Ga and S. The structure of the sample was examined with an X-ray diffractometer (XRD) and analyzed by using the Rietveld refinement. The crystal structure of the Ni0.9957Fe0.0₁Ga₂S₄ was determined to be a trigonal structure of P-3m1 with lattice constants a_0 = 3.629 A, b0 = 3.629 Aand c0 = 11.996 A. The Mossbauer spectra of Ni0.9957Fe0.0₁Ga₂S₄ were recorded at various temperatures ranging from 4.2 to 300 K. The magnetic hyperfine field and the electric quadrupole interactions at 4.2 K were fitted, yielding the following results: Hhf = 112.7 kOe, △EＱ = 1.374 mm/s, θ = 48.0˚ Φ =0.0˚, η = 0.5 and R = 1.8. The charge state of Fe ions is ferrous Fe²+ as characterized by an isomer shift of δ = 0.653 mm/s at 300 K. The Mossbauer spectra show a large quadrupole interaction in Ni0.9957Fe0.0₁Ga₂S₄.