Enhanced magnetic and electrical properties of Y and Mn co-doped BiFeO3 nanoparticles

Multiferroic (Y, Mn) substituted BiFeO3 had been synthesized by a facial sol-gel method. The single phase polycrystalline nature of samples was confirmed from X-ray diffraction pattern. The average particle size was estimated to be around 30-32 nm from transmission electron microscopy. The magnetic properties of codoped nanoparticles had been studied using Bloch equation and the estimated value of the Bloch constant was found to be much larger than usual ferromagnetic materials. Coercivity values for different temperature is used to calculate the blocking temperature and found to lie above room temperature. The dc electrical transport properties were studied in the temperature range 298- 523 K and explained using a Motts 3D variable range hopping model and the density of states was estimated near the Fermi level. The ac electrical data were found to follow the correlated barrier hopping model. Well-developed PE hysteresis loops were observed in codoped nanoparticles, which were attributed to a decrease in oxygen vacancies, bismuth volatisation due to doping and an increase of the effective potential barrier height for charge carriers. (C) 2014 Elsevier B.V. All rights reserve