Effect of Nb substitution on the structural, dielectric and magnetic properties of multiferroic BiFe1−xNbxO3 ceramics

► Effect of Nb5+ ion doping in structure, dielectric and magnetic properties of multiferroics BiFeO3 was studied. ► The result suggests the limit of dissolubility of Nb5+ ions in BiFeO3. ► The lowering of dielectric loss tangent by Nb5+ addition in the measured temperature range suggesting the control of oxygen vacancy and improved resistivity. ► The observed increase in magnetic parameter Mr with Nb5+ doping reflects the corresponding increase in the suppression of spin spiral with a continual change in lattice parameters and different exchange pathways owing to the distortion created by Nb5+ doping, changing the statistical distribution of Fe3+/Fe2+ as a result of charge compensation. ► The increase in absolute value of magnetocapacitance with increasing magnetic field, BiFe1−xNbxO3 is expected to show magnetoelectric coupling below Neel temperature.