Superconductivity of FeSe_0.5Te_0.5Thin Films Grown by Pulsed Laser Deposition

Abstract

FeSe 0.5 Te 0.5 thin films with a PbO-type structure are successfully grown on MgO(100) and LaSrAlO 4 (001) substrates from FeSe 0.5 Te 0.5 or FeSe 0.5 Te 0.75 polycrystalline targets by pulsed laser deposition. The film deposited on the MgO substrate (film thickness: ∼55 nm) shows superconductivity at 10.6 K (onset) and 9.2 K (zero resistivity). On the other hand, the film deposited on the LaSrAlO 4 substrate (film thickness: ∼250 nm) exhibits superconductivity at 5.4 K (onset) and 2.7 K (zero resistivity). This suggests the strong effect of substrate materials and/or the c -axis length on the superconducting properties of FeSe 0.5 Te 0.5 thin films.