LaNiO3 films with tunable out‐of‐plane lattice parameter and their strain‐related electrical properties

LaNiO3 (LNO) thin films were grown using pulsed laser deposition. The c-axis, i.e., out-of-plane lattice parameter of the films was controlled reproducibly by using different substrate materials and by variation of oxygen partial pressure and growth temperature. The out-of-plane (c-axis) strain of LNO deposited on LaAlO3 with increasing oxygen pressure changed from positive to negative. All the films show an excellent metallic conductivity with positive resistivity temperature coefficient. Lowest resistivity was about 300 µΩ cm. At high and low temperatures, the resistivity is explained by electron–phonon scattering and electron–electron interaction, respectively. In addition, the resistivity shows a clear dependence on the c-axis strain of LNO films. With increasing strain, the resistivity increases. However, this effect is much more pronounced for negative c-axis strain. Strain-dependent resistivity of LNO films on LAO at the indicated measurement temperatures. The inset is a typical AFM image of the LNO film surface.