Microstructures of thin film La2−xSrxCuO4 on SrTiO3 and LaAlO3

Abstract The microstructures of thin films of (103) La 2− x Sr x CuO 4 on (101) SrTiO 3 , and (001) films on (001) SrTiO 3 and (001) LaAlO 3 are investigated by transmission electron microscopy (TEM). Essentially, single crystal films of the (103) orientation are found for films grown on vicinal substrates of the appropriate miscut. The growth morphology of two-variant films, (103) and (103)', grown on substrates with little (≤1°) or no miscut are compared. A surface step morphology is found for single-variant growth, whereas two-variant growth produces an undulated surface because of the inhibited growth of the domain boundaries. Plan-view TEM images show the two-variant domains elongated in the [010] direction, with an aspect ratio of 10. An unknown interface structure - 10A thick is shown for the (103) oriented films. A new shear planar defect structure, involving edge sharing of the CuO 6 octahedra, is found in (001) films on (001) LaAlO 3 .