Making the most of the magnetic and lattice entropy changes

Recent discoveries of novel materials exhibiting a magnetocaloric effect that is strongly enhanced by the magnetoelastic coupling - the so-called giant magnetocaloric effect materials - stimulated an unprecedented expansion of research related both to the fundamentals of the phenomenon and potential future applications of these materials in continuous magnetic cooling near room temperature. The subject of this work is two fold. On one hand, systems exhibiting the giant magneto caloric effect may be prone to hysteresis, and may exist in nonequilibrium, phase-separated states, thus requiring a special care when their intrinsic physical properties are of interest. On the other hand, in order to harvest most of the magnetocaloric potential of a specific compound, both the magnetic and lattice degrees of freedom of the material must be precisely controlled. (C) 2008 Elsevier B.V. All rights reserved.