Effect of partial substitution of Ni by Co on the magnetic and magnetocaloric properties of Ni₅₀Mn₃₅In₁₅ Heusler alloy

The magnetic and magnetocaloric properties of Ni₄₈Co ₂Mn₃₅In₁₅ were studied using magnetization and heat capacity measurements. The magnetic entropy change (δS_M) was evaluated from both magnetizing and demagnetizing fields. An inverse S _M for the magnetizing and demagnetizing processes were found to be 20.5 and 18.5 J kg^-1 K^-1, respectively, for δH 5 T at the martensitic transition (T T_M). The normal S_M was found to be -5.4 J kg^-1 K^-1 for both fields at the paramagnetic/ferromagnetic transition (T = T_C). The effective refrigeration capacity at T_M and T_C for magnetizing field was found to be 268 and 243 J/kg (285 and 243 J/kg for the demagnetizing field), respectively. We have also estimated the density of states, the Debye temperature, and the inverse adiabatic temperature change to be 4.93 states/eV f.u., 314 K, and -3.7 K, respectively, from the measured heat capacity data.