Due to the simple layered structure, isostructural FeSe and FeSe0.5Te0.5 are clue compounds for understanding the principal mechanisms of superconductivity in the family of Fe-based superconductors. High-pressure magnetic, structural and Mössbauer studies have been performed on single-crystalline samples of superconducting FeSe0.5Te0.5 with Tc = 13.5 K. Susceptibility data have revealed a strong increase of Tc up to 19.5 K for pressures up to 1.3 GPa, followed by a plateau in the Tc(p) dependence up to 5.0 GPa. Further pressure increase leads to a disappearance of the superconducting state around 7.0 GPa. X-ray diffraction and Mössbauer studies explain this fact by a tetragonal-to-hexagonal structural phase transition. Mössbauer parameters of the non-superconducting high-pressure phase indicate less covalency of FeSe bonds. Based on structural and susceptibility data, we conclude about a common character of Tc(p) diagrams for both FeSe and FeSe0.5Te0.5 superconductors.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Mössbauer spectroscopy
- high pressure
- iron chalcogenides
- synchrotron X-ray diffraction