Nanoscale piezoresponse and magnetic studies of multiferroic Co and Pr co-substituted BFO thin films

Piezoresponse Force Microscopy (PFM) technique has been employed to acquire out-of-plane (OPP) piezoresponse images and local piezoelectric hysteresis loop in rhombohedrally distorted Bi _1-xPr _xFe _1-yCo _yO ₃ [x = 0, 0.05; y = 0.05] polycrystalline thin films fabricated via chemical solution deposition method. PFM images revealed that piezoelectric contrast is dependent upon the film composition. Furthermore, negative self-polarization effect was observed in the cobalt substituted BFO film. Well saturated local piezo-hysteresis loops were monitored and an increase was noticed in the piezoelectric coefficient (d ₃₃) value with cobalt doping (25.1 pm/V) whereas with Pr co-substitution in BFCO film, the piezoelectric behavior was almost suppressed. Pr and cobalt co-substituted film exhibited the lowest leakage current density. Magnetic behavior (M-H curves) exhibited nearly eight times enhancement in the saturation magnetization values in the Co- and Co-Pr substituted films. The present study provides the different elements' substitution effect on the local piezoelectric and magnetic properties of BiFeO ₃ multiferroic thin film.