Island structure and growth of pulsed laser deposited YBa2Cu3O7−x superconducting thin films

Surface and grain topography of YBa 2 Cu 3 O 7− x epitaxial thin films grown on (100) NdGaO 3 using pulsed laser deposition has been studied using atomic force and scanning tunneling microscopy under ambient conditions. X-ray diffraction and transmission electron microscopy results support the force microscopy findings. Parametric studies of the effect of substrate temperature, annealing time and deposition rate were performed on 33 nm thick films. The observed island re-orientation as a function of time-at-temperature suggest that under our epitaxial growth conditions, the nuclei ripening time can be on the order of seconds. Implications for the observed island structure on transport and microwave surface resistance properties are briefly discussed.