Magnetocaloric properties of compounds with first order phase transition: Hysteresis effect

In this paper we theoretically discuss the magnetocaloric effect in compounds undergoing first order phase transition, taking into account the hysteresis effect. For this purpose we use a microscopical model of localized magnetic moments including the magnetoelastic interaction. Our calculations show that in compounds undergoing first order transition with large magnetoelastic coupling, the magnetocaloric potentials Delta S-iso and Delta T-ad depend on the direction of the temperature variation. Moreover, our calculations also show that the magnetocaloric potential Delta S-iso around a first order phase transition can be calculated using magnetization data via the Maxwell relation only if the hysteresis is negligible. (C) 2011 Elsevier B.V. All rights reserved.