Estimating spontaneous magnetization from a mean field analysis of the magnetic entropy change

The magnetocaloric effect is a common property of all magnetic systems, corresponding to a temperature change under a diabatic conditions (Delta T-ad) or a change in magnetic entropy in isothermal conditions (Delta S-M), for a given applied magnetic field change. Delta T-ad can be directly measured under adiabatic conditions and in directly estimated from specific heat measurements. DSM can be indirectly estimated from specific heat measurements or magnetization measurements (the usual approach). Early work on the study of ferromagnets used direct measurements of Delta T-ad to determine the spontaneous magnetization for a given temperature value. In this work, we use DSM obtained from isothermal magnetization measurements to estimate the spontaneous magnetization, comparing this result to mean-field fittings from a novel scaling method, discussing the validity and usefulness of this approach from considerations from the Landau theory of phase transitions. (C) 2009 Elsevier B.V. All rights reserved.