Investigations on the structural, magnetic and optical properties of Sr-Zr co-doped BiFeO3 multiferroic powders

Sr-Zr co-doped multiferroic BiFeO3 powders are synthesized using sol-gel technique. The effect of Sr-Zr co-doping on the structural, magnetic and optical properties is investigated. X-ray diffraction demonstrates that the crystal structure transforms and there is no impurity phases present even in a high doping concentration. Scanning electron microscopy and transmission electron microscopy indicate that the Sr-Zr co-doping leads to a decrease in particle size with the Bi0.80Sr0.20Fe0.95Zr0.05 sample having a particle size of 20-50 nm. With the Sr-Zr co-doping, the nanopowders change to be soft ferromagnetic from antiferromagnetic. The room-temperature remnant magnetization is enhanced by the co-doping, from 0.015 emu/g for the pure BiFeO3 to 0.237 emu/g for the Bi0.80Sr0.20Fe0.95Zr0.05 sample. The optical band gap shows an increasing trend with co-doping.