Magnetostructural transition and magnetocaloric effect in Ni55Mn20Ga25 single crystals -: art. no. 094435

A first order transition from a paramagnetic-austenite phase to a ferromagnetic-martensite phase occurring in off-stoichiometry single crystals of Ni2MnGa at 313 K presents unique features due to the multifunctional character of the magnetic shape memory alloy. A remarkable magnetocaloric effect, associated with an entropy change up to Delta S approximate to-86 J kg(-1) K-1 and an adiabatic temperature change Delta T approximate to 2.2 K, accompanied by mechanical strain Delta epsilon >= 3% have been observed in samples subjected to changes of the applied magnetic field Delta H=4x10(6) A/m (approximate to 5 T). The effects of magnetic field, temperature, and stress on the entropy variation Delta S are quantified and compared.