Superconductivity of FeSe${}_{1-x}$Te${}_x$ Thin Films Grown by Pulsed Laser Deposition

Abstract

FeSe${}_{1-x}$Te${}_x$ thin films with PbO-type structure are successfully grown on MgO(100) and LaSrAlO${}_4$(001) substrates from FeSe${}_{1-x}$Te${}_{x+d}$ polycrystalline targets by pulsed-laser deposition. The film deposited on the MgO substrate (film thickness $\sim$ 63 nm) shows superconductivity at 6.7 K (onset) and 5.5 K (zero resistivity). On the other hand, the film deposited on the LaSrAlO${}_4$ substrate (film thickness $\sim$ 52 nm) exhibits only the onset of superconducting transition at 2.6 K, but does not show zero resistivity. This indicates the strong influence of epitaxial strain to superconducting properties of FeSe${}_{1-x}$Te${}_x$ thin films.

15 pages, 4 figures