Effects of substrate temperature on the growth and properties of SrRuO₃ and CaRuO₃ thin films

We report the observation of a low-temperature secondary growth orientation in SrRuO₃ thin films grown on LaAlO₃ substrates by pulsed laser deposition. This growth phase is present in crystalline films grown at substrate temperatures below ~600 °C and occurs in combination with the standard (110) oriented growth observed in films grown at higher temperatures. This secondary growth orientation does not occur in films of CaRuO₃ grown on LaAlO₃ at the same temperatures, presumably due to lattice mismatch considerations. We report for the first time the effects of the change in growth temperature from 200 to 800 °C on the orientation, lattice parameter, mosaicity and resistivity of both SrRuO₃ and CaRuO₃ films. We also discuss the dependence of the ferromagnetic transition temperature in the SrRuO₃ thin films on the growth temperature, as determined from the temperature dependence of the resistivity.