Influence of the doping of Ti~(4+) ions on electrical and magnetic properties of Mn_(1+x)Fe_(2-2x)Ti_xO_4 ferrite

摘要

ac conductivity and magnetic behaviour have been studied for a series of polycrystalline ferrite with general formula Mn_(1-x)Fe_(2-2x)Ti_xO_4, (0 < = x < = 0.5), prepared using a conventional solid-state reaction technique. The results of ac conductivity show that sigma_(ac) increases as the frequency and the temperature increase; whereas it decreases as Ti content increases except for a sample x = 0.1. The values of activation energies E_f for conduction process are determined from Arrhenius plots, and the variations of these activation energies as a function of composition have been discussed. The conduction mechanism used in present study have been discussed in the light of electron exchange between Fe~2 and Fe~3 ions and hole hopping between Mn~(+3) and Mn~(+2) ions at the octahedral B-sites. It observed that the saturation magnetization decreases with increase Ti~(4+) substitution, which is explained by the weakening of the exchange in the system according to Neel's molecular field model.