Fabrication of highly resistive La–Zn co-substituted spinel strontium nanoferrites for high frequency devices applications

The spinel La–Zn co-doped strontium nanoferrites having general formula of Sr_1-xLa_xFe_2-yZn_yO₄ (0.0≤x ≤ 0.1, 0.0≤y ≤ 1.0) have been synthesized. X-ray diffraction studies have been revealed successful fabrication of ferrites. Scanning electron microscopy results have shown that size of the particle of the ferrite samples lie in nano-range. DC electrical resistivity at room temperature increases with La³⁺ and Zn²⁺ ions concentration while dielectric parameters and AC conductivity decreases with concentration of these ions. Frequency dependent behavior of dielectric parameters has shown that values of these dielectric parameters decrease with frequency initially at lower values of frequency and then become almost constant at higher values of frequency. Electrochemical impedance spectroscopy data shows that the charge transfer phenomenon is mainly controlled by grain boundaries. Further, enhanced DC resistivity ranging from 1.08 × 10⁹ to 1.67 × 10⁹ Ω cm and low dielectric loss values of the La–Zn co-doped strontium nanoferrites suggest their applications in high frequency devices.