Tailoring the multiferroic properties of BiFeO3 by co‐doping Er at Bi site with aliovalent Nb, Mn and Mo at Fe site

Single phase multiferroic undoped BiFeO3 notoriously suffers due to the poor spin–charge coupling resulting in limitations to device applications. The present work focuses on the tailoring of its multiferroic and magnetoelectric coupling properties by synthesizing multiferroic Bi0.95Er0.05Fe0.98TM0.02O3 (TM = Nb, Mn and Mo) ceramics. The ferroelectric, magnetic, current leakage measurements and magnetoelectric effect were investigated. XRD along with the Reitveld refinement results confirms that all the samples possess perovskite based rhombohedral structure and reveals that doping of (Er, Nb), (Er, Mn) and (Er, Mo) induced the crystallographic distortion in the BFO lattice and hence induced a variation in the bond lengths and bond angle. Dual doping significantly enhanced the electrical, magnetic properties and magnetoelectric coupling as compared to BiFeO3. Doping has lowered the leakage current by three to four orders compared to BFO. The lattice distortion, reduced leakage current and destruction of spin–cycloidal structure could be the origin for these improved features. The (Er, Nb) doped BiFeO3 yields enhanced ferroelectric character with the maximum polarization value of 0.46 µC/cm2, maximum ME coupling of 0.22 mV/cm at a magnetic field of 130 G, an improved magnetization with a remanance value of 0.0903 emu/g and the lowest leakage current density. Figure (a) illustrates the variation of the electric polarization at different fields for the undoped and doped BiFeO3. Figure (b) illustrates the Current leakage density variation as a function of the applied electric field.