J. Phys. IV France 115 (2004) 105
DOI: 10.1051/jp4:2004115013
Magnetocaloric and shape-memory effects in Ni-Mn-Ga ferro-magnetic alloys
J. Marcos1, L. Mañosa1, A. Planes1, F. Casanova2, X. Batlle2, A. Labarta2 and B. Matínez31 Departament d'Estructura i Constituents de la Matèria, Facultat de Física, Universitat de Barcelona, Diagonal 647, 08028 Barcelona, Catalonia, Spain
2 Departament de Física Fonamental, Facultat de Física, Universitat de Barcelona, Diagonal 647, 08028 Barcelona, Spain
3 Institut de Ciència de Materials de Barcelona, CSIC, 080193 Bellaterra, Spain
Abstract
We show that an isothermal entropy change can be induced in Ni-Mn-Ga by the
application of moderate magnetic fields. This magnetocaloric effect is
originated by two different contributions: (i) the magnetostructural
coupling which takes place at the length scale of martensitic variants and
magnetic domains (mesoscopic coupling) and (ii) the microscopic
spin-phonon coupling. The first contribution is intimately related to the
magnetic shape-memory property and controls the magnetocaloric effect for
small inducing fields. The latter contribution is dominant for high fields.
© EDP Sciences 2004