Structural properties of epitaxial SrCuO2 thin films on SrTiO3 (001) substrates

Thin films of SrCuO2 with tetragonal structure have been epitaxially grown on SrTiO3 (001) substrates by high-oxygen pressure sputtering technique. The interface structure between SrCuO2 and SrTiO3 and configuration of defects in SrCuO2 thin films have been characterized by means of high-resolution transmission electron microscopy. Two types of film–substrate interface structure coexist and are determined as bulk–SrO–TiO2–Sr(O) –CuO2–Sr–bulk and bulk–SrO–TiO2–SrO–Sr(O) –CuO2–Sr–bulk. The planar faults with double SrO atomic layers in {100} planes in SrCuO2 thin films are observed, which mainly arise from the coalescence of these two types of film–substrate interface structure. Meanwhile, planar faults in {110} planes are observed in thin films and structural models are proposed.