Studies of the microstructures of YBa 2Cu 3O 7- x/La 0.67Ca 0.33MnO 3 heterostructural films

The structures of YBa ₂Cu ₃O _{7- x} (YBCO) thin films grown on SrTiO ₃ substrates with and without La _0.67Ca _0.33MnO ₃ (LCMO) buffer layer were investigated by high resolution X-ray scattering techniques. All the films are demonstrated to be c-axis oriented. X-ray analysis shows that the introduction of the LCMO buffer does not improve the quality of the YBCO film. It was found that the LCMO and the YBCO monolayers are in different strain states for different samples. In the YBCO/LCMO heterostructure, there exists misorientation between the film and the substrate. The interface roughness of YBCO/LCMO, as well as the surface roughness of all layers was obtained. There exists a non-designed cap layer on the upper surface of the YBCO layer in the YBCO/LCMO heterostructure.