Giant low field magnetocaloric effect and magnetostructural coupling in MnCoGe1-xInx around room temperature

Effects on substitution of Ge by In on structural and magnetic properties are studied in MnCoGe1-xInx compounds. A small amount of In (2% and 5%) dopant can shift the martensite transformation temperature to room temperature and make it overlap with Curie temperature window, which results in a spin-lattice coupling and a large conventional magnetocaloric effect. Giant values of magnetic entropy change (△SM) are obtained in both magnetizing and demagnetizing processes in the vicinity of the magnetostructural transition. The maximum values of |△SM| for MnCoGe0.95In0.05 reach 21.4 and 25.4 J/kg K for a small magnetic field change △H = 2-0 and 0-2 T, respectively, which make it promising for room temperature magnetic refrigeration applications.