An Investigation of the Magnetic and Structural Characteristics of Li-Ni ferrite nanoparticles

Nanoparticles of Li-Ni ferrite (LiNi₀.₅Fe₂O₄) were synthesized through the sol-gel auto combustion method, employing lithium nitrate, nickel nitrate, and ferric nitrate as precursors, with citric acid acting as a chelating agent. The samples were annealed at temperatures (as-burnt, from 400 to 800 °C). The impact of various calcination temperatures on the crystalline structure and magnetic characteristics of the LiNi₀.₅Fe₂O₄ nanoparticles was meticulously investigated through X-ray diffraction (XRD) and a vibrating sample magnetometer (VSM). From XRD analysis, crystallite size D determined for the most intense (311) peak using Scherrer’s formula. An increase in crystallite size was observed with higher annealing temperatures in the range of 28.50-41.345 nm, while coercivity with range 47.9-154.5 Oe showed an initial rise before decreasing as crystallite size grew. Variations in saturation magnetization (range 6.23-8.02 emu/g) and 1attice constant (range 8.291-8.295 °A) displayed a similar trend, decreasing at 400 °C and 600 °C but increasing at 800 °C.