Unique growth of self-oriented LaNiO₃ thin films prepared by a chemical solution deposition method

Abstract

We investigated the relationship between the self-orientation and process conditions of self-oriented LaNiO₃ (LNO) thin films fabricated by a chemical solution deposition method. The LNO thin films were deposited on Pt-coated Si, SiO₂/Si, glass, c-plane sapphire, and stainless-steel substrates, which have crystal structures different from that of LNO. Increasing the heating rate during the transition from 200 °C (pre-heating) to 380 °C (pyrolysis) enhanced the self-orientation of the resulting LNO thin films. The LNO thin films deposited on the various substrate materials exhibited (h00) self-oriented growth because Pb(Zr_0.52Ti_0.48)O₃ (PZT) thin films deposited on the self-oriented LNO thin films clearly adopted the (h00) preferential orientation. As a unique behavior of PZT/LNO bilayer structures, the PZT upper layer has stronger (h00) oriented growth than that of the underlying self-oriented LNO layer.