Large refrigeration capacities near room temperature in Ni2Mn1−xCrxIn

We report on the observation of large refrigeration capacities near room temperature in Ni2Mn1−xCrxIn Heusler alloys. The alloys exhibit the L21 cubic crystal structure and undergo a second order ferromagnetic to paramagnetic phase transition. The respective Curie temperatures vary with Cr concentration from 315 K to 290 K. Net refrigerant capacities of up to 60 J/kg and 168 J/kg are observed in the alloys for applied magnetic fields of 20 kOe and 50 kOe, respectively. Due to the second order phase transition, the materials do not exhibit any hysteresis loss or other problems usually associated with materials exhibiting first order phase transitions. The observed refrigeration capacities in Ni2Mn1−xCrxIn are higher than those observed in many Heusler alloys with first order magnetic transitions.