Preparation of alpha-axis-oriented YBa2Cu3Ox superconducting films on MgO substrates with PrBa2Cu3Ox buffer layers

We prepared high-quality a-axis-oriented superconducting YBa2Cu3Ox (YBCO) films on (100)MgO substrates using the c-axis-oriented PrBa2Cu3Ox (PBCO) buffer layer and the a-axis-oriented cubic YBCO seIf-template layer. The YBCO template layers deposited at a low substrate temperature (T-s) on MgO substrates without the PBCO buffer layers were found to Nm into orientation other than a-axis orientation by annealing at a higher temperature after the deposition. The in-plane aligned c-axis-oriented PBCO layer was inserted between the a-axis-oriented cubic YBCO laver and the MgO substrate to stabilize the template layer. As a result, the YBCO film deposited at higher T-s on these layers was found to be a-axis-oriented with a full width at a half-maximum (FWHM) of the (200) rocking curve of 0.58 degrees. an FWHM of (200) diffraction of 0.18 degrees, a critical onset temperature around 90 K and a critical zero temperature of 70 K.