Magnetostructural transitions with a critical behavior in Y-doped MnCoGe compounds

The behavior of magnetic and structural transitions in Y substituted MnCoGe system is investigated in this study. Both Mn and Ge deficiencies in MnCoGe phase are induced by a single-site Y doping. The structural transition temperature thus shifts to lower temperatures and creates a Curie temperature window as wide as 86 K. The largest magnetic entropy change of about 15.6 J/kg∙K and refrigerant capacity of about 132.8 J/kg are obtained in these compounds. The samples at the boundary of the temperature window show a critical phenomenon, which is characterized by a magnetostructural transition during the cooling process and separate magnetic plus structural transitions during the heating process. This makes it possible to determine the contribution from the magnetic transition to the total entropy change in magnetostructural transition, which is 23–26% in present system.