Study on velocity mode of 57Fe M?ssbauer spectroscopy and determination of lattice dynamics in Fe 3S 4

摘要

57Fe M?ssbauer spectroscopy studies on chemically synthesized greigite Fe3S4have been conducted with a unique velocity mode, known as constant velocity with slope, which allows detection of subtle changes and in-depth details of sextets in the spectra. Accurate determination of the overlapped sub-spectra corresponding to tetrahedral Fe3+(A) and octahedral Fe2.5+(B) sub-lattices has been made based on the special velocity mode. Estimation of Debye temperatureθDfrom the temperature dependent central shift (CS) values gives the values: 805?±?10?K and 760?±?10?K for A- and B-sites, respectively. The discrepancy of twoθDvalues reveals different lattice vibration between A- and B-sites. The Lamb-M?ssbauer factor ratiofB/fAis found to be 0.98 at room temperature. The different low-temperature behaviors of hyperfine magnetic field for tetrahedral A- and octahedral B-sites are observed.