Epitaxial LaFeAsO1−xFxthin films grown by pulsed laser deposition

Superconducting and epitaxially grown LaFeAsO 1− x F x thin films were successfully prepared on (001)-oriented LaAlO 3 substrates using pulsed laser deposition. The prepared thin films show exclusively a single in-plane orientation with the epitaxial relation and a full width at half-maximum value of 1°. Furthermore, resistive measurement of the superconducting transition temperature revealed a T c,90% of 25 K with a high residual resistive ratio of 6.8. The preparation technique applied, standard thin film pulsed laser deposition at room temperature in combination with a subsequent post-annealing process, is suitable for fabrication of high quality LaFeAsO 1− x F x thin films. A high upper critical field of 76.2 T was evaluated for magnetic fields applied perpendicular to the c -axis and the anisotropy was calculated to be 3.3 assuming single band superconductivity.