Experimental investigation on structural, dielectric and magnetic properties for Ni_0.5Cu_0.2Cd_0.3La_xFe_2-xO₄ dense ceramics materials with theoretical fitting judgements

Ni_0.5Cu_0.2Cd_0.3La_xFe_2-xO₄ bulk ceramics with step size 0.015 were prepared following the sol–gel synthesis process and sintered for 5 h at 1200 ºC. The structural, dielectric, magnetic, and electrical transport properties have been analyzed at room temperature. The structural analysis was performed through X-ray Diffraction method and then Rietveld refinement to analyze the crystal phase formation of the ceramics compound. As the frequency increases the dielectric constant and loss tangent decreases by following the dependence on the frequency nature of ceramics. The center of the modulus semicircles is found under the real axis and thus indicates the prepared ceramics as non-Debye type relaxation. In addition to dielectric analysis, impedance spectroscopy measurements were performed to study the impedance nature, and the measured data was also fitted to the famous Cole–Cole spectrum. The contribution of grain and grain boundary on the resistance and capacitance for La substitution has been calculated from the theoretical fitted data. Enhancement of saturation magnetization, initial permeability and conductivity was observed due to the replacement of Fe by La.