Magnetization enhancement in nanosized MgFe2O4 prepared by mechanosynthesis

The magnetization enhancement in nanoscale mechanosynthesized MgFe2O4 is reported and is discussed in terms of a modified core-shell model, in which a competition between the effects of spin canting and site exchange of cations plays a decisive role. Because of the nearly random distribution of cations, the surface shell of nanoparticles exhibits an effective magnetic moment that is about 2 times larger than that of the particle core. The thickness of the magnetically active'' surface shell is calculated from the size-dependent magnetization measurements. (c) 2007 Elsevier B.V. All rights reserved.