Experimental and Theoretical Realization of Morphology and Frequency Tuned Charge Transport Dynamics in Co-Zn Doped SrM Hexaferrite: Electrical, Impedance and Relaxation Realm

The present report comprehensively investigates the influence of sol-gel synthesized cobalt and zinc-substituted SrFe12O19 on the morphological, structural, dielectric, and electrical characteristics. XRD analysis revealed that the substituents successfully replaced Fe3+ ions, leading to the existence of magneto-plumbite structure of M-type hexaferrite in all synthesized samples with some minor traces of CoFe2O4 in Sr Co0.8Zn0.8Fe10.4O19. With increasing the substitution level, SEM micrographs exhibited the formation of grain clusters. The electrical parameters had been investigated in the 20 Hz to 2 MHz frequency range. In the low-frequency region, both dielectric constant and loss tangent decreased with Co-Zn substitution. Sr Co0.8Zn0.8Fe10.4O19 sample shows the minimum value of AC conductivity 3.95 x 10-5 omega-1m-1 in the high-frequency region. Both the electric modulus and impedance spectra exhibit non-Debye behavior in all samples. The Cole-Cole plots ( M'' versus M') reveal the existence of a single semicircular arc in the x = 0.0 sample, caused by the grain boundary contribution.