3.2 SEM Analysis

3.2 SEM analysis
Fig. 3(a-f) shows the SEM micrographs of all the samples. It can be observed that all the particles are agglomerated in some irregular shapes, have no clear boundaries and are loosely packed. Moreover, the samples exhibit inhomogeneous grain size distribution [20]. Micrographs also confirm the decrease in grain size with substitution of Pr. The electrical and magnetic properties of ferrites are largely affected by the grain size. It is evident from micrographs that the average grain size of the prepared samples increases with the Pr content. These results are in good agreement with XRD data.Simila results have been reported in literature for RE substituted spinel ferrites [21, 22].
3.3. Electrical resistivity measurements
The
Moreover, the explanation offered for electrical resistivity stands same for activation energy. Table 2 shows that the activation energy in the ferrimagnetic region is lower than that in the paramagnetic region. The result is in agreement with the theory developed by Irkin and Turov [28]. The conduction at a lower temperature i.e. below Curie temperature(Tc) (ferrimagnetic region) is due to hopping of electrons [29] between Fe2+ and Fe3+ ions. The conduction at a higher temperature i.e. above Curie temperature (paramagnetic region) is due to hopping of polarons [29]. It is due to the fact that poloran hopping required comparatively more energy than that of electrons hopping as in electron hopping the both types of charges move freely in the crystal lattice. This is the main factor for lowering of the activation energy in ferrimagnetic than paramagnetic
8 shows the magnetization M (emu/g) as function of external magnetic field H (Oe) of CuPryFe2-yO4 (y= 0.00, 0.02, 0.04, 0.06, 0.08, 0.10) ferrites. Under the applied magnetic field, the clear hysteric behavior was observed. The narrow loops indicate the soft nature of these spinel ferrites. Furthermore, the hysteresis loop is used to calculate the different magnetic parameters like coerecvity (Hc), remanence (Mr) and magnetization (Ms). The saturation magnetization was calculated by magnetization curve at Hmax and showed a decreasing trend with the increasing Pr content as depicted in Fig.