PREPARATION AND MICROSTRUCTURE OF SRCUO2/(SR0.5CA0.5)CUO2 EPITAXIAL MULTILAYERS WITH THE INFINITE-LAYER STRUCTURE

Multilayer thin films of SrCuO2/(Sr0.5Ca0.5)CuO2 with an infinite-layer structure have been prepared on (100) SrTiO3 single crystals by multitarget rf magnetron sputtering. The structural analyses of the multilayers were carried out by means of x-ray diffraction (XRD), secondary ion-mass-spectroscopy (SIMS), and transmission electron microscopy (TEM). Heteroepitaxial growth of the SrCuO2 and (Sr0.5Ca0.5)CuO2 layers was confirmed to be with the c-axis perpendicular to the (100) SrTiO3 surface. The XRD and SIMS measurements revealed that the compositional modulations of the multilayer films were successfully constructed as we designed. However, in the TEM images, there existed planar dislocations parallel to the ac- and bc-planes, which went across the boundaries of the SrCuO2 and (Sr0.5Ca0.5)CuO2 layers. The resistivity of the multilayer films showed semiconductor-like behavior with temperature, and there was no relation between electric properties and modulation wavelength.