Studies on the multiferroic properties of (Zr, Cu) co-doped BiFeO₃ prepared by sol–gel method

Nanoparticles of Bi_1−x Zr _x Fe_0.98Cu_0.02O₃ (x = 1 %, 2 %, 3 %, 4 %, 5 %) were prepared by sol–gel method. The influences of Zr dopant on the characteristics of polycrystalline BiFeO₃ (BFO) have been studied. X-ray diffraction study confirms the formation of nanocrystalline rhombohedral phase without distortion. The average crystallite size is found to vary from 31 to 60 nm. All the samples exhibited well-saturated ferromagnetic hysteresis. A notable increase in the saturation magnetization (M_s) and remnant magnetization (M_r) has been observed with increase in dopant percentage. Improved ferromagnetic and magnetoelectric behavior of BFO nanoparticles is found to be the result of doping. The Zr and Cu doping has improved the ferroelectric properties of the BFO. The variation in the surface morphology is also attributed to Zr doping of BiFeO₃.