Effect of Li1+ ion on the physico-chemical properties cation distribution of sol-gel synthesized Ni-Zn spinel ferrite nanoparticles

This study presents the synthesis and comprehensive analysis of polycrystalline LixNi0.6Zn0.4-2xFe2+xO4 (with x values of 0.00, 0.01, 0.03, 0.05, 0.07, 0.09) ferrites, with lithium (Li) concentrations ranging from x = 0.00 to 0.09, utilizing the sol-gel auto-combustion method followed by sintering at 800 degrees C for 8 h. A nuanced examination of the lattice constants obtained from the X-ray diffraction patterns revealed a slight decrement from 8.386 to 8.357 & Aring;, exhibiting a linear pattern across the Li concentration spectrum. The crystallite sizes, as determined by the Scherrer formula, fluctuated between 31 and 40 nm, while Field Emission Scanning Electron Microscopy indicated an increase in average grain size from 146 to 186 nm due to nanoparticle agglomeration. High-Resolution Transmission Electron Microscopy analysis of nanoparticles yielded an average grain size of similar to 69 nm and an interplanar spacing of approximately 0.1521 nm. Magnetic characterization revealed a decrease in saturation magnetization from 87 to 70 emu/g with increasing Li content, with the lowest Ms observed for the x = 0.09 sample, indicating the material's soft magnetic nature. Raman and Fourier-transform infrared spectroscopy confirmed the retention of the conventional spinel structure, characterized by both tetrahedral and octahedral iron coordination, and illuminated the impact of co-existing iron phases on the structural anomalies observed. These findings contribute valuable insights into the effects of lithium substitution on the structural, morphological, and magnetic properties of Ni-Zn ferrites, underscoring their potential for various technological applications.