Microstructure and magnetization study of Li and Li–Zn ferrites synthesized by an electron beam

Abstract

Lithium ferrites are widely used in high frequency electronic devices. The present work reports structural and magnetization analysis of lithium (Li0.5Fe2.5O4) and lithium-zinc (Li0.4Fe2.4Zn0.2O4) ferrites synthesized by electron beam heating (RT) of powdered and compacted samples. The synthesis was carried out at 600 and 750 °C for up to 120 min using 2.4 MeV electron beam generated by an ILU-6 pulsed electron accelerator. The characteristics of the samples synthesized by RT were compared with the ones of samples obtained by traditional thermal heating under the same temperature and time conditions. From XRD and thermomagnetometric analyses, α-Li0.5Fe2.5O4 ordered spinel phase and Li0.5(1−x)Fe2.5−0.5xZnxO4 ferrite phase with different zinc substitution were formed from Fe2O3/Li2CO3 and Fe2O3/Li2CO3/ZnO reagents, respectively. RT synthesis significantly increases the rate of interaction between the initial powders and, as a consequence, the rate of ferrite phase formation. In this case, lithium-containing ferrites can be successfully achieved from compacted powders at 750 °C, which is lower than the temperature of synthesis in conventional thermal heating. The average crystallite sizes calculated from the XRD and BET analyses were 114 nm for Li, 120 nm for Li–Zn ferrites and 142 for Li, 150 nm for Li–Zn, respectively. The specific saturation magnetization and Curie temperature were estimated and are 60 emu/g for Li, 70 emu/g for Li–Zn ferrites and 632 °C for Li, 492 °C for Li–Zn ferrites, respectively. The data obtained in this work are of considerable interest for the creation of a technology for producing ferrites at low synthesis temperatures.