Nature of Preferred Orientation of YBa2Cu3Ox Thin Films

To clarify a preferential orientation of YBa2Cu3O x thin films, the growth parameters of a- and c-axis oriented thin films are investigated. YBa2Cu3O x thin films are grown on different lattice-mismatching substrates, such as Nd: YAlO3 (001), LaAlO3 (100), NdGaO3 (110), PrGaO3 (001), SrTiO3 (100) and MgO (100) by pulsed laser deposition (PLD) to determine the a- and c-axis preferential orientation phase diagrams. These a- and c-axis preferential orientations are controlled by the lattice constant of the substrate, the substrate temperature during deposition, the oxygen pressure in the growth chamber, and the laser power. The existence of a c-axis oriented YBa2Cu3O x layer between the substrate and a-axis oriented YBa2Cu3O x thin films is explained.