Structural and magnetic properties of nanocrystalline nickel ferrite (NiFe2O4) synthesized in sol-gel and combustion routes

Abstract

Nano-crystalline Nickel ferrite (NiFe2O4) was synthesized in sol-gel and combustion methods with different chelating agents like PVA, citric acid and urea. In the synthesis, the amount of chelating agent was taken exactly equal to the optimal output mass of the nickel ferrite which is unlike to conventional sol-gel or combustion method of synthesis. The powder X-ray diffraction technique was performed to identify the structure of the nickel ferrite and crystallite sizes of these samples were measured. The crystallite size was observed to be in the range of 6–14 nm. Dynamic light scattering was performed to analyze the particle size distribution. DLS measurements revealed that the average particle diameters for the three samples were in the range of 10–25 nm. All the three samples were studied for magnetization and the measurements were carried out using Vibrating Sample Magnetometer at room temperature. Among the three samples, sample synthesized via citric acid auto combustion method displayed a highest magnetization of 27.05 emu/g and sample synthesized through combustion method with Urea displayed low saturation magnetization owing to its smaller crystallite size and improper development of crystal planes. Magneto-crystalline anisotropy (K1) constants were determined using law of approach and the three samples displayed an order of 105 erg/cm3.