Eur. Phys. J. B 32, 303-307 (2003)
https://doi.org/10.1140/epjb/e2003-00102-y

Giant entropy change at the co-occurrence of structural and magnetic transitions in the Ni_2.19Mn_0.81Ga Heusler alloy

¹ IMEM - CNR, Parco Area delle Scienze, 43010 Fontanini, Parma, Italy
² INFM and Dipartimento di Fisica, Università di Parma, Parco Area delle Scienze, 43100, Parma, Italy

Corresponding author: ^a solzi@fis.unipr.it

Received: 27 September 2002
Revised: 17 February 2003
Published online: 11 April 2003

Abstract

We have studied the isothermal entropy change around a first-order structural transformation and in correspondence to the second-order Curie transition in the ferromagnetic Heusler alloy Ni_2.15Mn_0.85Ga. The results have been compared with those obtained for the composition Ni_2.19Mn_0.81Ga, in which the martensitic structural transformation and the magnetic transition occur simultaneously. With a magnetic field span from 0 to 1.6 T, the magnetic entropy change reaches the value of 20 J/kg K when transitions are co-occurring, while 5 J/kg K is found when the only structural transition occurs.