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.
