Influence of Cu-doping and thickness on metallic conductance in PrNio3 thin films

Abstract

The need of present day technology is exploring new materials with rich fundamental physics and various technological applications. Perovskite oxides, exhibiting lot of practical applications serve as a potential candidate for physics now a days. Rare earth nickelates (RNiO3) are abundant with many physical phenomenon of fundamental importance such as phase transition, strongly correlated effects, high temperature superconductivity, Colossal Magnetoresistance (CMR).All these properties are highly controllable in thin film form. We have deposited two series (12 nm and 5 nm) of PrNi1-xCuxO3 (x =0-0.1) thin films on (LaAlO3)0.3(Sr2Al-TiO6)0.7 – (LSAT) single crystal substrate using pulse laser deposition and studied the effects of Cu-doping and thickness variation on the electronic properties. For series-1 (12 nm), the undoped PrNiO3 film shows a metal to insulator phase transition and thermalhysteresis around 100 K. A fractional doping of 1.0 atomic percentage of Cu at Ni site is able to supress the insulating phase completely and thereby driving the system towards steady metallicity throughout the temperature range below 300 K. However, at lower dimensions in series-2 with 5 nm thickness, these effects of Cu-doping and metallicity is reduced. Resistivity data of all the films fit to power-law equation show non-Fermi Liquid behaviour (NFL). A switching from one type of NFL to another type has been observed due to both, Cu-doping and thickness variation. Further, the fitting parameters show a systemic variation with increasing Cu content indicating that the carrier injection by even a fractional Cu-doping is highly effective in bringing metallicity in the system due to band-filling effects. We have observed that cu-doping has induced a complete metallic and they can be used for electrode applications.