STUDY OF STRUCTURAL, MAGNETIC, AND ELECTRICAL PROPERTIES OF Mg SUBSTITUTED Ni-Cu-Cd BULK FERRITES OBTAINED FROM NANOCRYSTALLINE POWDERS.

Abstract

Bulk ceramics with optimized density are highly prioritized over ferrite nanoparticles to fabricate devices for their optimal magnetic saturation, lower coercivity, and anisotropy, enhanced resistance, etc. To achieve such bulk specimen using Ni0.5-yMgyCu0.2Cd0.3Fe2O4 disc and toroid samples are sintered at 1423 K keeping the heating and cooling rate at 10 K and 5 K respectively. In this course, structural as well as theoretical Rietveld analysis, optical, and magnetic dielectric and electrical properties have been analyzed using these bulk samples. XRD has explored structural properties and after that these values have analyzed with the Rietveld refinement procedure and obtained goodness of χ2 (1–2) value and other parameters such as lattice parameters, crystal structures, cation distribution, and maximum entropy mapping. Surface morphology and grain size have examined from the as-grown surface without further polishing and annealing by electron microscopy and revealed a decreasing trend of grain size 6.1 μm to 4.2 μm. UV–Vis spectroscopy characterization ensured optical properties for bulk as well as nanopowders and the band gap has been found in the range of 1.4 to 1.6 eV and is increasing with Mg content. Magnetic hysteresis loop exhibits a less decreasing nature up to y = 0.3 of magnetic saturation along with the Law of Approach to saturation which compiles magnetic anisotropy. The temperature dependent magnetization curves exhibit a sharp decreasing value (i.e. dM/dT minimum) at Curie point, decreasing from 630 K to 505 K with increasing Mg content. At 3 T magnetic field the changes in relative cooling power value have been found in the range 53.82 Jkg-1 to 37.79 Jkg-1 which could be considered as potential for magnetocaloric refrigeration. Impedance spectroscopy and other electrical characterization techniques were also employed to study the material's electrical properties. These measurements revealed that Mg2+ substitution improved the samples' electrical conductivity and dielectric properties. The findings of this research show the possibility of Mg2+ substitution as a strategy for tuning the structure, magnetic and electrical properties show the possibility of MLCI application in Ni-Cu-Cd bulk ferrite.