Very large refrigerant capacity at room temperature with reproducible magnetocaloric effect in Fe 0.975 Ni 0.025 Rh

We present the results of magnetocaloric effect (MCE) measurements on Fe 0.975 Ni 0.025 Rh. The MCE is estimated using both the isothermal field-dependent magnetization and the temperature-dependent magnetization in constant magnetic fields. We find a very large effective refrigerant capacity of nearly 492.8 J kg −1 , with the hot end at about 307 K, which is reproducible over many field cycles. We compare this refrigerant capacity with those of two well known systems, namely Gd 5 Ge 1.9 Si 2 Fe 0.1 and MnFeP 0.45 As 0.55 , which show a large MCE near room temperature, and also with our earlier results on the parent Fe–Rh alloy. The large effective refrigerant capacity in our sample is one of the largest achieved yet at room temperature with a significant improvement over the parent Fe–Rh system.