Strain-induced metallic behavior in PrNiO₃ epitaxial thin films

Abstract

Electrical transport properties of RNiO₃ (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 LaAlO₃ (1 0 0) substrate. Unlike the polycrystalline solid, PrNiO₃ films showed metallic behavior. The first-order metal-to-insulator transition observed in polycrystalline solids is suppressed in RNiO₃ films. The effect of lattice strain in the films influencing the transport properties has been studied by varying the thickness of PrNiO₃ film on LaAlO₃ (1 0 0) and also by growing them on SrTiO₃ (1 0 0) and α-Al₂O₃ ( 1 1 0 2) 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 LaNiO₃ film is also influenced by a similar strain effect.