Abstract
We have successfully synthesized Chromium (Cr3+) and aluminium (Al3+) co-doped nano-scale (9 nm-17 nm) spinel magnesium ferrite of the composition Mg(Cr-0.5_Al-0.5 )(x)Fe2-xO4 (for x = 0.00, 0.10, 0.15, 0.20, 0.25, 0.30) utilizing inexpensive materials and very easy one step sol-gel combustion technique using urea as fuel. Composition dependent impedance analysis revealed the existence of insulating grain boundaries around relatively conducting grains. Magnetic analysis shows unusual magnetic behaviour which has been explained on the basis of various interacting parameters arising due to low dimensionality of the grains and because of lattice defects due to dopant species. A scheme of cation distribution in tetrahedral (A) and octahedral (B) sites has been devised through the analysis of magnetic data. The cation distribution scheme was further utilised to suggest a general expression for the magnetization trend observed between the given doping limit.