Correlation among the structural, electric and magnetic properties of Al 3+ substituted Ni-Zn-Co ferrites.

This study explored the structural, electrical, and magnetic properties of diamagnetic aluminium (Al 3+ ) substituted nickel-zinc-cobalt (Ni-Zn-Co) mixed spinel ferrites, though the research on this area is in the infancy stage. Single-phase cubic spinel structures with the Fd 3̄ m space group of the synthesized Ni 0.4 Zn 0.35 Co 0.25 Fe (2- x ) Al x O 4 (0 ≤ x ≤ 0.12) ferrite samples were confirmed by X-ray diffraction (XRD) analysis. The average particle size ranged from 0.67 to 0.39 μm. Selected area electron diffraction (SAED) patterns were indexed according to the space group Fd 3 m , representing the particle's crystallinity. The optical band gaps ranged from 4.784 eV to 4.766 eV. Frequency-dependent dielectric constants and ac conductivity measurement suggested that the prepared ferrites were highly resistive. Relaxation times were reduced to a low value from 45.45 μs to 1.54 μs with the composition x . The Curie temperatures ( T c ) were 615-623 K for all samples. Real part permeabilities ( μ / ) were relatively stable up to an extended frequency range of 10 6 Hz with relative quality factors (RQF) of around 10 3 . Tuning of the properties indicates that the fabricated ferrites may be promising for high-frequency electronic devices.