57Fe nuclear resonant inelastic scattering of Fe1.1Te
- 77 Downloads
This study reports results of 57Fe Mössbauer spectroscopy and nuclear resonant inelastic scattering (NRIS) in Fe1.1Te. The Fe-specific partial phonon densities of states (PDOSs) were extracted from the observed spectra. No detectable change at the tetragonal-monoclinic phase transition around 65 K was observed. Therefore the variations in lattice constants and/or distortion in FeTe4 tetrahedron through the structural transition was minute. From the observed Fe-PDOS, the Lamb-Mössbauer factor was 0.90(3) at 10 K and the Debye temperature was evaluated as 300(10) K. In 57Fe Mössbauer spectroscopy, the clear magnetic spittings of spectra were measured below Néel temperature. The obtained values of isomer shifts showed characteristics of Fe2+ species and clear difference with the phase transition was observed in temperature dependence of quadrupole splitting (QS). The change of QS must be caused by substantial change of the charge density distribution around the Fe site. This suggests that the band structure or the nature of the Fe-Te bonds becomes highly anisotropic. These results might provide additional information about the respective mechanisms for FeTe1−xSex superconductivity.
KeywordsNuclear resonant inelastic scattering Synchrotron radiation Iron based superconductors
We thank the technical staff at SPring-8 for their support. We are also thankful to the entire staff of the Research Center for Low Temperature and Materials Sciences, Kyoto University for their support in measurement of magnetic properties using Quantum Design MPMS-5S system. This research was supported by the CREST project “Studies on Nuclear Resonant Scattering Methods for Materials Science”, Japan Science and Technology Agency. The experiments reported in this study were performed at the BL09XU and BL11XU of SPring-8 with the approval of the Japan Synchrotron Radiation Research Institute (Proposal No. 2009B0086, 2011A3501, and 2011B3501).
- 19.Goldanskii, V.I., Herber, R.H. chap. 1: Chemical Applications of Mössbauer Spectroscopy, p 34. Academic Press, New York and London (1968)Google Scholar