AB-ORIENTED YBA2CU3O7 THIN-FILM GROWN ON C-AXIS LAYER BY RADIO-FREQUENCY SPUTTERING

YBa2Cu3O7 films can be grown on different substrates by the off-axis ac magnetron sputtering method. Films in the ab orientation tend to grow at a lower substrate temperature than c-axis films. However, as the temperature is lowered, all the substrates we have tested, except for SrTiO3, form amorphous phases that degrade the quality of the films being made. In this manuscript it is shown that if a thin layer of c-axis film is deposited on the substrate first, then it effectively reduces the formation of the amorphous phases and improves the film quality significantly.