Growth of SrRuO3 thin films on MgO substrates by pulsed laser ablation

Abstract

SrRuO3 thin films have been grown on MgO substrates using pulsed laser ablation deposition. The orientation of the SrRuO3 films changes from the [001] or [110] direction normal to the substrate surface to become predominantly [100] as the thickness of the SrRuO3increases from 50 to 360 nm. This leads to a change in the magnetic response of the SrRuO3 films and to a dramatic improvement in the superconducting properties of YBa2Cu3O7−δ films grown on top of the SrRuO3 layer. The domain structures and the surface morphology of SrRuO3 films grown on MgO change as the thickness of the film increases. The 50 nm thick SrRuO3 film grown on an MgO substrate nucleates as rectangular islands, 0.5 to 1 μm in diameter. As the thickness increases to 185 nm, oriented grains ∼1 μm in size are observed. We have noted a different microstructure for the SrRuO3 thin films grown on SrTiO3 substrates. The 185 nm thick SrRuO3 film grown on a SrTiO3 substrate shows a step like growth pattern.