Effect Of Substrate On Superconducting And Magnetic Properties For The Epitaxial Fese0.5te0.5 Thin Films

High quality FeSe0.5Te0.5 (FST) epitaxial thin films were successfully prepared on SrTiO3 (STO), MgO and LaAlO3 substrates with a TiO2 buffer layer by pulsed laser deposition method, respectively. We present the results of a collaborative study on the superconducting and magnetic properties of the three types films, such as the critical temperature T (c), the anisotropy, and the critical current density J (c). A stronger matching between film and substrate plays an important role in enhancing the superconducting and magnetic properties. FST film on STO substrate shows the high superconducting transition temperature T (c) about 14.6 K and the largest critical current density J (c) above 10(6) A cm(-2) at 4 K in self-field. In addition, the high-angle annular dark field imaging implies the interface sharpness at FST/TiO2 heterostructure, contributing to a deep understanding of bonding for the iron-based superconductors.