Magnetic properties and phase diagram of ZnxNi1−xFe2O4: High-temperature series expansions

Abstract Using mean field theory and high-temperature series expansions (HTSEs), extrapolated with the Pade approximants method, the effect of Zn doping on magnetic properties of NiFe 2 O 4 ferrite spinel has been studied. The nearest neighbour super-exchange interactions for intra-site ( J AA , J BB ) and inter-site ( J AB ) of the Zn x Ni 1− x Fe 2 O 4 ferrites spinels, in the range 0≤ x ≤1, have been computed using the probability approach, based on Mossbauer data. The paramagnetic Curie–Weiss temperature θ and the Curie temperature T C are calculated as a function of Zn concentration. The critical exponent γ associated with magnetic susceptibility is calculated. The spin correlation functions intra-plane and inter-plane have been also computed and compared with exchange couplings. The obtained theoretical results are in good agreement with experimental ones obtained by magnetic measurements and Mossbauer spectroscopy.