Synthesis of Nanocrystalline Ni_(0.5)Zn_(0.5)Fe_2O_4 by Aerosol Route and Its Characterization

摘要

Nano-size particles of Ni_(0.5)Zn_(0.5)Fe_2O_4 ferrite were prepared through aerosol route. The solutions of iron, nickel and zinc nitrates were mixed in stoichiometric proportion, passed through a pneumatic nebulizer, to get very fine mist (aerosols), and a furnace at ～600°C in air atmosphere. Through various events in succession, metal atoms form ferrite in air. The average particle size was found to be 16±6 nm which increased to 80±8 nm after annealing at 1000°C. The room-temperature magnetic moment of the sample as obtained and after annealing it at various temperatures indicate that the saturation magnetization increases from 1.80 to 72.8 emu/g, while remanent magnetization increases from 0.28 to 25.0 emu/g. Moessbauer spectrum of the sample at room temperature exhibited a doublet with δ(Fe) = 0.33 mms~(-1) and ΔE_Q = 0.78 mms~(-1) suggesting superparamagnetic nature. However, after annealing at 1000°C this doublet got converted into two magnetic sextets with B = 52.4 T and 49.0 T suggesting increase in particle size on annealing. These observations are in conformity with Transmission Electron Microscope (TEM) and X-Ray Diffraction (XRD) results that the particle size increases after annealing the sample at higher temperatures.