Thickness dependent superconducting properties of FeTe_0.55Se_0.45 thin films grown on YSZ substrates

The discovery of new high-temperature superconductors has long been a significant research issue in condensed matter physics. Iron-based superconductors (IBSs) have generated much research interest as the topological states in IBSs have been reported, suggesting a promising direction to realize topological superconductivity and great potential in various applications. Many attempts have been made to understand the origin of topological states in Fe-chalcogenide thin films in recent years. From this approach, we have fabricated superconducting thin film of different thicknesses (59 nm and 78 nm) from polycrystalline target FeTe_0.55Se_0.45 on YSZ single-crystalline substrates using pulse laser deposition (PLD) technique to study the structural, topological, and superconducting properties. Temperature-dependent resistivity curves show T_C ~ 15 K. The magnetotransport data have been used to calculate the upper critical field (H_C2) and coherence length (ξ) of grown thin films. From the magnetoresistance (MR) results, we have observed thickness dependence non-saturating linear magnetoresistance (LMR) in superconducting thin films, suggesting the presence of the possible topological superconducting state in the grown thin films.