Microstructure of laser-ablated superconducting La 2 CuO 4 F x thin films on SrTiO 3

Thin films of lanthanum cuprate were grown on SrTiO 3 substrates by pulsed laser deposition and made superconducting (T c ∼ 38 K) through the process of post-deposition fluorination using elemental fluorine. A microstructural analysis showed that the [ 1 10] zone of the film grows parallel to the [100] zone of the SrTiO 3 substrate, reducing the lattice mismatch from 37.5% to 2.4%. At the film–substrate interface there is an intermediate layer 3–4 nm thick and twin-related grains emanate from this region. Stacking faults are present in the bulk of the film, with misoriented subgrains present at the deposit surface.