EPITAXIALLY INDUCED DEFECTS IN SR-DOPED AND O-DOPED LA2CUO4 THIN-FILMS IS GROWN BY MBE - IMPLICATIONS FOR TRANSPORT-PROPERTIES

In this paper, the critical role played by various types of defects an d strain relaxation mechanisms in high-T-c thin films is highlighted a nd illustrated with examples. The defects are essential for providing adequate diffusion channels for oxygen ingress during the cooling step in c-axis thin films. The operation of strain relaxation mechanisms n ecessitated by the lattice mismatch between film and substrate can imp ose a compressive or tensile biaxial pressure, which either increases or reduces the critical temperature.