Effect of annealing temperature on structural and magnetic properties of BaFe12O19 hexaferrite nanoparticles

In the present work, barium hexaferrite nanoparticles were synthesized through a co-precipitation route in the presence of a high concentration hydroxide ion at low temperature. Effect of annealing temperature on structure, morphology and magnetic properties of nanoparticles was investigated by X-ray diffraction (XRD), Fourier transform infrared (FTIR), field emission scanning electron microscopy (FE-SEM) and vibrating sample magnetometer (VSM). XRD patterns of the samples along with FTIR analysis confirmed the formation of crystalline hexagonal ferrite phase for powders annealed above 700 degrees C. Also, the FE-SEM images showed that particle size increased from few nanometers to micrometers by increasing annealing temperature from 90 to 1200 degrees C. Moreover, the VSM results indicated that, with increasing annealing temperature, magnetization and coercivity increased and reached maximum value of 46 emu g(-1) and 5278 Oe, respectively, for the sample annealed at 900 degrees C. Also, the low-temperature (90 degrees C and 500 degrees C) annealed samples were superparamagnetic in nature at room temperature due to their near-zero coercivity and remanence. (C) 2013 Elsevier Ltd and Techna Group S.r.l. All rights reserved.