125Te Synchrotron-Radiation-Based Mossbauer Spectroscopy of Fe1.1Te and FeTe0.5Se0.5

The Te-125 Mossbauer spectra of Fe1.1Te and FeTe0.5Se0.5 were measured using synchrotron-radiation-based Mossbauer spectroscopy. The hyperfine field of Te in the antiferromagnetic phase of Fe1.1Te was evaluated to be 4(1)T at 20 K, and this hyperfine field is considered to be due to the transferred hyperfine field from Fe magnetic moments. The evaluated hyperfine field was comparatively large, suggesting the strong correlation with the magnetic moment of Fe that forms a double-stripe type magnetic structure. For the superconductor FeTe0.5Se0.5, no marked change in its Mossbauer parameters was observed below or above the superconducting transition temperature, indicating that the change in the electronic state of Te was small.