Mössbauer studies of Fe<inf>x</inf>NbS<inf>2</inf> (x = 0.25, 0.33 and 0.5)

Mössbauer studies of FexNbS2 (x = 0.25, 0.33 and 0.5) have been carried out for temperatures from 4.2K to about 715K. The iron exists in high spin divalent state for all the compositions. The temperature dependence of quadrupole splitting and center shift shows a reversible phase transition at about 600K and a possible disordering of Fe vacancies beyond this temperature for Fe0.25NbS2 and a reversible phase transition at 490K for Fe0.5NbS2. The hyperfine magnetic fields have been evaluated from the magnetically ordered spectra. The observed temperature dependent line intensities of the quadrupole doublet are attributable to the temperature dependence of the difference in the meansquare amplitude of vibrations parallel and perpendicular to the EFG axis. © 1983.