Strain-induced Metallic Behavior in $PrNiO_3$ Epitaxial Thin Films

Abstract

Electrical transport properties of $RniO_3$ (R=Pr, Nd, Sm) thin films grown by pulsed laser deposition have been studied. RNiO3 films grow in the (1 0 0) direction on a $LaAlO_3$ (1 0 0) substrate. Unlike the polycrystalline solid, $PrNiO_3$ films showed metallic behavior. The first-order metal-to-insulator transition observed in polycrystalline solids is suppressed in $RniO_3$ films. The effect of lattice strain in the films influencing the transport properties has been studied by varying the thickness of $PrNiO_3$ film on $LaAlO_3$ (1 0 0) and also by growing them on $SrTiO_3$ (1 0 0) and $\alpha-Al_2O_3 (1 \={1}02)$ substrates. Deviation in the transport properties is explained due to the strain-induced growth of the films. Further, we show that the transport property of a $LaNiO_3$ film is also influenced by a similar strain effect