Semiconducting epitaxial films of metastable SrRu0.5Sn0.5O3 grown by pulsed laser deposition

Abstract

Synthesis of the perovskite solid solution that forms between metallic SrRuO3 and insulating SrSnO3 is reported. This material is proposed as a conducting thin-film electrode/epitaxial-substrate material. While the bulk solid solution could not be formed, thin films of single-phase SrRu0.5Sn0.5O3 were grown on (001) KTaO3 single-crystal substrates by pulsed laser deposition. These films exhibit a commensurate in-plane lattice match with KTaO3 (a=3.989 Å); accordingly, the lattice constant of SrRu0.5Sn0.5O3 is larger than that of commonly used conducting-oxide thin-film electrodes (e.g., SrRuO3, LaNiO3, and YBa2Cu3O7−δ). The SrRu0.5Sn0.5O3 films were analyzed using x-ray diffraction, Rutherford backscattering, atomic force microscopy, Z-contrast transmission electron microscopy, and Hall effect measurements. The results revealed excellent atomic-scale structural properties, flat surfaces (13 Å rms roughness), and p-type conduction with a room-temperature resistivity of 16 mΩ cm.