Monte Carlo simulations of the magnetocaloric effect in magnetic Ni-Mn-X (X = Ga, In) Heusler alloys

Monte Carlo simulations were used for a detailed description of magnetic, martensitic and magnetocaloric properties of Ni(2+x)Mn(1-x)Ga (0.18 <= x <= 0.24) and Ni(50)Mn(34)In(16) Heusler alloys, which undergo a first-order magnetostructural phase transition. In the simulations we made use of magnetic exchange parameters which were obtained by ab initio calculations. Results of magnetic and lattice contributions to the total specific heat as well as the change in the isothermal magnetic entropy Delta S(mag) and the adiabatic temperature Delta T(ad) changes around the magnetic and magnetostructural transitions in an external magnetic field agree fairly well with available experimental data.