Fabrication of epitaxial conductive LaNiO3 films on different substrates by pulsed laser ablation

LaNiO3 (LNO) thin films were deposited on (1 0 0) MgO, SrTiO3 (STO) and LaAlO3 (LAO) crystal substrates by pulsed laser deposition (PLD) under 20 Pa oxygen pressure at different substrate temperatures from 450 to 750 °C. X-ray diffraction (XRD), ex situ reflection high energy electron diffraction (RHEED) and atomic force microscopy (AFM) were employed to characterize the crystal structure of LNO films. LNO films deposited on STO and LAO at a temperature range from 450 to 700 °C exhibit high (0 0 l) orientation. XRD ψ scans and RHEED observations indicate that LNO films could be epitaxially grown on these two substrates with cubic-on-cubic arrangement at a wide temperature range. LNO films deposited at 700 °C on MgO (1 0 0) substrate have the (l l 0) orientation, which was identified to be bicrystalline epitaxial growth. La2NiO4 phase appears in LNO films deposited at 750 °C on three substrates. The epitaxial LNO films were tested to be good metallic conductive layers by four-probe method.