Enhanced physical compatibility in manganite/cuprate multilayer with high-quality interface

A systematical study of the relationship between microstructure of interface and physical properties is performed on La0.67Ca0.33MnO3(LCMO)/YBa0.85Eu0.15Cu3O7 (YEBCO) multilayer. Flat and chemically well-defined interface is found for the film grown on (001) oriented SrTiO3 (STO) substrate. High resolution transmission electron microscopy observations reveal that nano-scale periods of multilayer structure can effectively suppress the second phase inclusions that are commonly seen in superconducting single layer. The coexistence of ferromagnetism and superconducting behavior is evidenced in [(LCMO)/(YEBCO)]6/STO multilayer. In contrast, when using Y stabilized ZrO2 single crystals (YSZ) as substrate, pyramid-like defects and disordering layer form because of the lattice mismatch between the film and the substrate. The superconducting transition response is lost in this case but large magnetoresistance is obtained. These results indicate an extensive rearrangement of ferromagnetic domain under applied magnetic field at extended defects dominated [(LCMO)/(YEBCO)]6/YSZ multilayer. The decoupling of ferromagnetism and superconductivity in [(LCMO)/(YEBCO)]6/YSZ multilayer is ascribed to the missing high-quality interface nature that otherwise present in [(LCMO)/(YEBCO)]6/STO multilayer.