Synthesis and deciphering the effects of sintering temperature on structural, elastic, dielectric, electric and magnetic properties of magnetic Ni0.25Cu0.13Zn0.62Fe2O4 ceramics

In this study, Ni0.25Cu0.13Zn0.62Fe2O4 polycrystalline ferrites were synthesized through a solid-state reaction route. The standard techniques such as XRD, FTIR, FESEM, EDX, and VSM were employed to analyze and understand the crystallized single-phase, crystallite size, functional groups, morphology and magnetic properties. FTIR and XRD analyses revealed the different band modes in structure, formation and the compositions of the cubic spinel structure. FESEM revealed that the grain size increases as the sintering temperature increases and the presence of the required elements as per the stoichiometric ratio were ascertained by EDX. The longitudinal wave velocity (Vl), transverse wave velocity (Vt), mean elastic wave velocity (Vm), bulk modulus (B), rigidity modulus (n), Young's modulus (Y), Poisson ratio (sigma) and Debye temperature ((D)) were evaluated. The elastic moduli were corrected to zero porosity through Hasselman and Fulrath model and Ledbetter and Datta model. The dielectric constant increases with sintering temperature which is accounted for the partial reduction of Fe(3+)to Fe(2+)and exhibited dispersive behavior as a result of Maxwell-Wagner-type interfacial polarization. The small polaron hopping phenomenon is responsible for the electrical conduction process. The initial permeability was found to increase with sintering temperature as a result of the increased densities and grain sizes. The Q-factor decreases and the cut-off frequency shifts toward the lower frequency side with sintering temperature. The magnetic parameters drastically deteriorate with sintering temperature which may be ascribed to the sample inhomogeneity and presence of intragranular porosity.