Influence of Ce doping and thickness on the structure and non-Fermi liquid behavior of LaNiO3 thin films

Abstract

Thin films of La1-xCexNiO3 (x = 0, 0.1, and 0.3) are grown with two different thickness (8 and 24 nm) on single-crystal LaAlO3 (001) (LAO) substrate using pulsed laser deposition. The films with x = 0 and 0.1 are highly oriented toward the (00l) axis despite different thickness, whereas the higher doped films (x = 0.3) of both thicknesses show two crystallographic orientations. A significant shifting of Raman modes is observed due to increased Ce doping, clearly indicating a large change in Ni–O–Ni bond-angle and NiO6 octahedra distortion. Also, Raman modes show a red-shift in all the thin films with increases in temperature. These films remain metallic until low temperatures. The resistivity increases with increased Ce doping as well as with increased thickness. The resistivity data fit well with the power-law equation, indicating a non-Fermi liquid state. This study helps to distinguish the effects of Ce doping and thickness on the structure and Raman modes.