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 Bi1−xPrxFe1−yCoyO3 [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 (d33) 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 BiFeO3 multiferroic thin film.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Local-piezoelectric characterization of Bi1−xPrxFe1−yCoyO3 [x = 0, 0.05; y = 0.05] films. ► Piezoresponse images revealed composition dependent piezoelectric contrast. ► Negative self-polarization effect in cobalt substituted BFO film. ► An increase in the piezoelectric coefficient (d33) value with cobalt doping. ► The substituted films showed nearly eight times higher magnetization.