Synthesis of zinc substituted barium hexaferrite nanoparticles and their magnetic performance

Abstract

Single phase M-type zinc substituted barium hexaferrite nanoparticles with molecular formula Ba sub(x) Zn sub(1-x) Fe sub(12)O sub(19) and x = 0.2, 0.4, 0.6 and 1.0 and mixed multiferroic material nanoparticles were obtained involving combustion synthesis via calcination of the combustion products at different temperatures using eco-friendly fuel. The systems were studied by X-ray Diffraction (XRD), Infra Red Spectroscopy (IR), Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS) and automated pulsed high field hysteresis loop tracer for their characterization, structure parameters, composition and magnetic property analysis. Particle size evaluation was done using XRD data after duly compensating for the microstrain on the nanoparticles which is partially responsible for broadening of XRD peaks. The final crystallite sizes of the nanoparticle materials in the pure phase had a very narrow size dispersion of less than 2 nm and were in the range of 14.5 nm to 16.1 nm and the crystallite sizes of the nanoparticle multiferroic particles were between 15.72 nm to 22.27 nm. Magnetic parameters such as saturation magnetization, coercivity and retentivity were found to depend on the fraction of Zn substitution in the sample. The saturation magnetization was found to be lower in case of the pure phase than the mixed multiferroics obtained at lower calcination temperature. For x = 1 the mixed multiferroic showed a maximum of 53.06 emu/gm whereas the nanoparticles of the pure phase of Ba sub(x) Zn sub(1-x) Fe sub(12)O sub(19) gave a maximum value of 35.87 emu/gm for the saturation magnetization. The coercivity value of the pure Phase with x = 1 was much higher and was nearly double to that of the value obtained for the corresponding mixed multiferroic obtained at 450 degrees C. The relevant analysis of magnetic data indicated that the materials were composed of single domain and superparamagnetic particles.