Effect of dopant concentration and annealing temperature on electric and magnetic properties of lanthanum substituted CoFe2O4 nanoparticles for potential use in 5G wireless communication systems

Abstract Dielectric-magnetic nanoparticles are the key component used in high-frequency devices employed in the 5G telecommunication system. Lanthanum-doped cobalt ferrites have shown remarkable properties to improve the functioning of the wireless system. In this context, CoLaXFe2-XO4 (x = 0, 0.025, 0.050, 0.075, 0.1) ferrite nanoparticles are synthesized using chemical coprecipitation technique. X-ray diffraction confirms cubic spinel structure with average crystallite size ranging from 17 to 42 nm. Fourier transform infrared spectra exhibit a characteristic band at ~575 cm-1 illustrating the formation of the ferrite phase. Magnetic properties show a non-linear variation with La3+ ions content as well as annealing temperature attributed to the complex inclusion mechanism involved in the substitution of Fe3+ ions by rare-earth ions. The formation of secondary phases at high annealing temperature had a significant effect on magnetic and dielectric properties. Saturation magnetization ranges from 21.6emu/g to 49.6emu/g and shows an increasing trend with annealing. The Nyquist plots indicate the dominant effect of grain boundaries in the conduction process. The La-doped annealed ferromagnetic ferrites possess a good crystalline structure with enhanced dielectric constant, high anisotropy constant, moderate saturation magnetization, and high Q-factor which makes them a superior choice in 5G wireless communication system.