Epitaxial growth of BaHfO sub(3) buffer layer and its structure degeneration analysed by Raman spectrum

BaHfO sub(3) (BHO) has been proposed as a new cap layer material for YBa sub(2)Cu sub(3)O sub(7- delta ) (YBCO) coated conductors. Highly c-axis oriented BHO cap layer has been deposited on ion-beam assisted deposition-MgO buffered Hastelloy tapes by direct-current-magnetron sputtering method. The epi-growth of BHO films combined with its properties is investigated in details. The degenerated cubic crystal structure of BHO film is confirmed by Raman spectrum analysis. XRD theta -2 theta scan, phi -scan and omega -scan reveal an excellent c-axis alignment with good in-plane and out-of-plane textures for BHO cap layers. SEM and AFM investigations show BHO cap layer a dense and crack-free morphology. Subsequently pure c-axis orientation YBCO film was epitaxial grown on such BHO cap layer successfully, shown BaHfO sub(3) a potential cap layer material for coated conductors.