Electron diffraction (LACBED) and HRTEM Moire fringe pattern study of stress in YBaCuO thin film on MgO

Epitaxial stresses are studied by means of Large Angle Convergent Beam Elec tron Diffraction technique and Moire fringe pattern obtained by High Resolu tion Transmission Electron Microscopy in pulsed laser deposited thin films of YBaCuO on MgO substrate. Grains with their c-axis parallel to the interf ace (c//) grow from the substrate up to the outer surface of the film. The c// grains, embedded in the c perpendicular to host matrix, are studied fro m investigations of cross-sectional sample, by both LACBED performed on the MgO substrate just beneath the different orientations of the thin film, an d by the Moire fringe pattern obtained by tilting the interface of the samp le. The broadening of the Bragg lines present in the LACBED disk together w ith the direction of the Moire fringes, clearly indicate that the c// orien ted grains embedded in a c perpendicular to oriented YBaCuO matrix are unde r stress.