Induction of superconductivity in pulsed laser ablated La 2CuO 4 thin films by post-deposition fluorination

Abstract

Pulsed laser ablation has been used to fabricate La 2CuO 4 thin films. Superconducting properties have been successfully induced in the films by an ex-situ, post-ablation annealing process in F 2 gas resulting in a T c (onset) of 36 K. The presence of two slightly different c-axis expanded phases in the X-ray diffraction data of the fluorinated films implies a degree of inhomogeneity in F 2 uptake. Critical current densities ( J c) and the irreversibility line have been established from hysteresis cycles. A J c of ∼ 10 6 A cm −2 for a typical film was observed at 10 K in zero field.