Magnetic studies of nanosized nickel ferrite particles synthesized by the citrate precursor technique

Nanometer size NiFe2O4 particles were synthesized by the Citrate precursor technique and control of solid state reactivity yields the monophasic ultrafine NiFe2O4 which were characterized by XRD, SEM and BET surface area measurements. Interestingly, single domain particles were found to form the linear chain like clusters because of strong magnetic dipolar interactions. The low saturation magnetization values were attributed to the spin noncollinearity predominantly at the surface. The Hopkinson effect is exhibited by an assembly of noninteracting single domain particles and is explained within the mathematical formalism given by the Stoner and Wohlfarth model. (C) 1998 Elsevier Science S.A.