Study on the high resistivity and resonant frequency characteristics of Eu-doped NiZnCo ferrites.

To fulfill the urgent demand for materials suitable for contemporary high-frequency applications, Eu-substituted Ni 0.55 Zn 0.35 Co 0.1 Eu x Fe 2- x O 4 (NZCEF, 0 ≤ x ≤ 0.10) composite ferrites were successfully synthesized by a solid-state reaction method, demonstrating characteristics apt for high-frequency functionalities. Detailed examination via SEM and EDS confirmed the compositional purity of these ferrites. Microstructural analysis indicates that the incorporation of europium results in a reduction of the average grain size in NZCEF composites, enhancing the material's densification. Measurements of resistivity and dielectric properties reveal that Eu doping affects the concentration of Fe2+ and Fe3+ ions as well as lattice defects within the ferrite, thereby leading to higher dielectric constants and resistivity (ρ , 6.51 × 108 Ω m). Magnetic analysis confirms that the substitution with Eu ions significantly increases both the coercivity and the ferromagnetic resonance frequency (f r), from 25.7 Oe and 445 MHz to 45.73 Oe and 1.22 GHz, respectively. This improvement is attributed to changes in grain size and domain wall motion. Consequently, Eu3+-substituted NZCEF ferrites exhibit superior electromagnetic properties, making them ideal candidates for advanced high-frequency material applications. [ABSTRACT FROM AUTHOR]