Entropy change of a Ni45.5Co4.5Mn37In13 single crystal studied by scanning calorimetry in high magnetic fields: Field dependence of the magnetocaloric effect
Résumé
By using differential scanning calorimetry, direct entropy variations have been recorded along the martensitic transformation of a Ni45.5Co4.5Mn37In13 single crystal in various magnetic fields. A large negative magnetocaloric effect associated to the transformation from virtually non-magnetic martensite to ferromagnetic austenite coexists with a weaker, positive effect related to the Curie transition in the latter phase. It is shown that the field-dependence of the maximum isothermal entropy change can be modelized by taking into account the interplay of both magnetocaloric contributions, as well as the intrinsic width of the martensitic transformation.