Magnetic properties of mixed Ni-Cu ferrites calculated using mean field approach

The magnetic properties of spinel ferrites [Fe1-(1-x)y3+Cu(1-x)y2+](A)[Nix2+Cu(1-x)(1-y)2+Fe1+(1-x)y3+](B)O-4 have been studied by the mean field theory(MFT) and high temperature series expansions (HTSEs) combined with the Pade approximants. The critical temperature, the saturation magnetisation(M-S) and the intra-sublattice exchanges interactions (J(AA)(x,y), J(BB)(x,y) and J(AB)(x,y)) are obtained by using a probability distribution law. The critical exponents associate with the magnetic susceptibility have been obtained. The effect of copper doping on the magnetic properties of nickel ferrites has been examined. (C) 2014 Elsevier B.V. All rights reserved.