Growth of SrxCa1−xCuO2 film and (CaCuO2)m/(SrCuO2)n superlattice by reactive sputtering

Abstract

The SrxCa1−xCuO2 thin films and [CaCuO2]m/[SrCuO2]n superlattices (SLs) have been prepared by multi-target off-axis rf magnetron sputtering on treated SrTiO3 (1 0 0) with periodic step arrays of atomic control on substrate surfaces. X-ray diffraction analyses have confirmed the formation of the tetragonal, infinite layer crystal structure with c-axis orientation. The obtained SLs and the SrxCa1−xCuO2 thin films showed semiconducting behavior. The SrxCa1−xCuO2 thin films with x=0.7 had remarkable resistive anomalies around 90 K and clear Meissner signals at temperature below 45 K. For the CaCuO2/SrCuO2 artificial SLs, SL chemical modulation was observed for structures with individual layers as thin as two unit cells. The peak attributed to the SL periodicity was also observed, indicating good control of the film growth.