Controllable synthesis of La3+ doped [formula omitted] (x = 0.0, 0.0125, 0.025, 0.0375, 0.05) nano-ferrites by sol-gel auto-combustion route

Abstract

Zn0.5Co0.25Cu0.25Fe2−xLaxO4(x = 0.0, 0.0125, 0.025, 0.0375, 0.05) ferrite powders with uniform distribution of ions and close-packed configuration were prepared via sol-gel auto-combustion route. XRD spectra showed the formation of spinel-phase cubic crystalline structure. SEM results revealed that the irregularity in size and shape of particles increases, and particle distribution uniformity decreases with La3+ concentration. Moreover, each curve of the UV–vis spectra revealed two optical energy band gaps. More importantly, DC resistivity (ρ) and the activation energy (ΔE) have minimum values at x = 0.0375. The dielectric loss was explained according to Maxwell-Wager space charge polarization. The P-E loop showed the ferroelectric nature of the synthesized samples. Moreover, VSM results revealed that the as-prepared samples possessed maximum saturation magnetization (MS = 56.77 ± 0.0283) and 8–12 GHz operating microwave frequency (ωm) range at x = 0.0375. All these results show the potential of Zn0.5Co0.25Cu0.25Fe1.9625La0.0375O4 ferrite powders for X-band microwave applications.