Modeling of the Magnetization and Magnetocaloric Effect in Ni2MnGa Heusler Alloy with the Effective Field Theory.

This study modeled and investigated the magnetocaloric effect in Ni2MnGa Heusler alloy characterized by its magnetic entropy change (ΔSm) and its refrigerant capacity (RCFWHM) by using the effective field theory. It was found that the peak of the negative magnetic entropy change (ΔSmpk) and the RCFWHM decreased as the external magnetic field increased, whereas the full width half maximum peak (δTFWHM) and the temperature (Tpk) of the ΔSmpk both increased. At higher external magnetic fields, δTFWHM and Tpk were close to each other, but the ΔSmpk and RCFWHM were separated from each other. The RCFWHM of the corner atoms (Ni1 and Ni3) was higher than those of the central atom (Ni5). This result revealed that corner atoms have an important role in the magnetocaloric properties of Ni2MnGa and other materials with a magnetocaloric effect. [ABSTRACT FROM AUTHOR]