Unusual Transition of Electrical and Magnetic Properties in the Nano to Bulk Transformation of Co-Zn Ferrites

Abstract

Phase transition in ferrite plays a vital role in hyperthermia, because this provides an idea to make the ferrite to be used in the areas, where the switching of conductivity is needed. Anomalous change in the lattice parameter was found with sintering temperature for zinc concentrations x = 0.7 and 0.5 substitution of Zn at cobalt site, in an inverse CoFe2O4 may give raise to a new property that will lead the technology to its best. The XRD patterns reveal the formation of single-phase cubic spinel with crystallite sizes in the range of 13–78 nm. The plot shows that gradually degenerated semicircle grows into a fully grown semicircle without any electrode effect, with temperature for all the samples. This results suggest grain and grain boundary contributed conductivity. Ms is found to increase linearly with particle size (i.e) for 13 nm (x = 0.7), Ms is 12 emu/g, for 18 nm (x = 0.5), Ms increases to 33 emu/g, whereas further increase in the particle to 19 nm (x = 0.3), Ms decreases to 32 emu/g due to single domain to multidomain transition indicating nanonature of the samples.