Enhanced dielectric and magnetic properties in multiferroic Bi0.99Y0.01Fe0.99Ni0.01O3 ceramic

An enhanced low-frequency dielectric constant, (ε′∼104), and ferromagnetic behavior at room temperature were observed in Bi0.99Y0.01Fe0.99Ni0.01O3 (BYFNO) ceramic sintered by a modified solid state reaction method. The anti-ferromagnetic (AFM) nature of BiFeO3 (BFO) changed to ferromagnetic (FM) with saturation magnetization, Ms, and coercivity Hc values of ∼0.03μB/f.u. and ∼250Oe, respectively at room temperature. The XRD patterns revealed that the co-doping of Y3+ and Ni2+ ions at the A− and B− sites of BiFeO3 (BFO) resulted in a rhombohedrally distorted perovskite structure. This result was discussed in terms of the modification of the cycloidal spin structure, presence of Ni2+ carriers and preservation of oxygen vacancy during the sintering process. This enhanced properties entitle the Bi0.99Y0.01Fe0.99Ni0.01O3 one of the few multiferroic materials that exhibits both significant ferromagnetic and dielectric behaviors at room temperature.