In this paper we discuss the determination of the s(Ha,T) entropy constitutive relation of magnetocaloric materials by means of heat flux calorimetry. In particular we discuss on a method to account for the temperature lag due to the finite thermal conductivity of heat flux. We show examples of materials without hysteresis: Gd and hydrogenated La(Fe-Mn-Si)13-H and with hysteresis: La-(Fe- Co-Si)13 and the Heusler Ni-Mn-Co-Sn. The resulting magnetocaloric properties, i.e. the specific heat capacity as a function of the magnetic field and the magnetic field induced entropy change are interpreted and discussed in terms of the ferromagnetic, electronic and structural contributions to the free energy and the entropy.
A physical insight into magnetocaloric materials by calorimetrry in magnetic fields / V., Basso; Sasso, CARLO PAOLO; Kuepferling, Michaela. - (2012), p. 15. (Intervento presentato al convegno Thermag V, Fifth IIF-IIR International Conference on Magnetic Refrigeration at Room Temperature tenutosi a Grenoble, Francia nel 17-20 Settembre 2012).
A physical insight into magnetocaloric materials by calorimetrry in magnetic fields
SASSO, CARLO PAOLO;KUEPFERLING, MICHAELA
2012
Abstract
In this paper we discuss the determination of the s(Ha,T) entropy constitutive relation of magnetocaloric materials by means of heat flux calorimetry. In particular we discuss on a method to account for the temperature lag due to the finite thermal conductivity of heat flux. We show examples of materials without hysteresis: Gd and hydrogenated La(Fe-Mn-Si)13-H and with hysteresis: La-(Fe- Co-Si)13 and the Heusler Ni-Mn-Co-Sn. The resulting magnetocaloric properties, i.e. the specific heat capacity as a function of the magnetic field and the magnetic field induced entropy change are interpreted and discussed in terms of the ferromagnetic, electronic and structural contributions to the free energy and the entropy.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
