Effect of substrate temperature on the structural and electrical properties of La and Mn co-doped BiFeO3 thin films

Abstract

The effect of substrate temperature on the structural and electrical properties of multiferroic Bi0.90La0.10Fe0.95Mn0.05O3 (BLFMO) thin films deposited on Pt (111)/Ti/SiO2/Si substrate using pulsed laser deposition (PLD) has been investigated. Films with substrate temperature ranging from 450°C to 650°C have been deposited. The grain size and roughness are found to increase with substrate temperature. The film deposited at 575°C exhibits maximum remnant polarization around 39μC/cm2 and a coercive field of 400kV/cm. The cyclic fatigue study of the sample shows only 4% loss after 108cycles. Complex impedance study of the BLFMO thin films demonstrates electrical homogeneity of the sample. AC conductivity data has been fitted using Jonscher single power law, and value of n found to be <1 indicating translational hopping conduction mechanism. The lowest leakage current found is 4.37×10−6A/cm2 at 575°C. The leakage current mechanism is found to be dominated by space charge limited current and Fowler-Nordheim conduction mechanism.