Systematic effects of Ti doping on the electronic properties of LaNiO3 thin films

We have deposited a series of LaNi1–xTixO3 (x = 0–0.10) thin films on LaAlO3 (001) (LAO) single-crystal substrates using pulsed laser deposition (PLD) method and studied the effect of Ti doping on the structural and electronic properties. All the films are highly oriented towards the substrate (001) axis. The incorporation of Ti ions in LaNiO3 system causes an increase in the compressive strain. The temperature-dependent resistivity curves indicate that the films remain metallic even at low-temperature range. In spite of a lower percentage of variation in Ti doping, the overall resistivity of the system increases quite systematically with increase in Ti content. The power-law fitting of resistivity data show the non-Fermi behaviour of the system. Besides, a systematic blue shift of Raman modes is observed with increase in doping, which indicates a change in Ni–O–Ni bond angle and NiO6 octahedra distortion due to Ti doping in LaNiO3 thin films. The temperature-dependent Raman spectra show the red shift with increase in temperature in all the thin films. The observed systematic variations in resistivity and Raman modes both originated due to Ti doping in the system.