Characteristics of conductive SrRuO₃ thin films with different microstructures

Conductive SrRuO₃ thin films were epitaxially grown on (100) LaAlO₃ substrates by pulsed laser deposition over a temperature range from 650 °C to 825 °C. Well-textured films exhibiting a strong orientation relationship to the underlying substrate could be obtained at a deposition temperature as low as 450 °C. The degree of crystallinity of the films improved with increasing deposition temperature as confirmed by x-ray diffraction, transmission electron microscopy, and scanning tunneling microscopy. Scanning electron microscopy revealed no particulates on the film surface. The resistivity of the SrRuO₃ thin films was found to be a strong function of the crystallinity of the film and hence the substrate temperature during film deposition. A residual resistivity ratio (RRR = ρ300 K/ρ4.2 K) of more than 8 was obtained for the SrRuO₃ thin films deposited under optimized processing conditions.