Magnetocaloric Properties of Ni_(2+x)Mn_(1-x)Sn Heusler Alloys

摘要

We have investigated the magnetocaloric properties of Ni_(2+x)Mn_(1-x)Sn (x = 0, 0.05 and 0.1) Heusler alloys by using the dc-magnetization measurement technique. A reduction in the paramagnetic to ferromagnetic transition temperature (Curie temperature, T_C) has been observed with a substitution of Ni at the Mn site (from T_C appro× 349 K for x = 0 to appro× 317 K for x = 0.1 sample). With an increase in x, a very small reduction in the value of the magnetic entropy change -ΔS_M has been observed. The -ΔS_M values have been found to be appro×2.1, 1.8 and 1.5 J kg~(-1) K~(-1) for x = 0, 0.05 and 0.1 samples, respectively, for a magnetic field change from 0 to 30 kOe. The hysteresis loss has also been found to be very small for all the compositions. Moreover, a non-toxic as well as a cost effective nature of the studied Ni_(2+x)Mn_(1-x)Sn alloys can make them promising candidates for magnetic refrigeration near room temperature.