*3.2.1 Structural studies of Co0.65Zn0.35Fe2O4*

**Figure 5 (a)** shows the Rietveld refinement (space group: *Fd*¯ <sup>3</sup>*m*) of Co0.65Zn0.35Fe2O4 (CZFO) ferrite, which indicate spinel phase [32]. The value of χ<sup>2</sup> is 1.648. The lattice parameter of CZFO is found to be 8.4183 Å. A three-dimensional sketch of CZFO unit cell projected along the *c*-axis (**Figure 5(b)**). The inset of **Figure 5(a)** shows the SEM image of a CZFO pellet sample to displays densely packed grains with few scattered pores and voids. It is also reported in Ref. [32] that the high dielectric permittivity value is obtained. The ferrimagnetic-paramagnetic phase transition is ~640 K.
