Ab initio mechanical and thermal properties of FeMnP1−xGax compounds as refrigerant for room-temperature magnetic refrigeration

Abstract

Density functional theory was used to identify possible Fe₂P-type giant magnetocaloric FeMnP_1−xGa_x compounds. The calculated formation energies, elastic constants and phonon spectra confirm the energetic, mechanical and dynamical stability of hexagonal FeMnP_1−xGa_x compounds in both the ferromagnetic and paramagnetic states. The predicted magnetic moment, elastic properties, and Curie temperature of FeMnP_0.67Ga_0.33 are close to those obtained for FeMnP_0.67Ge_0.33 compounds using the same calculation scheme. The entropy changes and latent heat of FeMnP_0.67Ga_0.33 are similar with those of FeMnP_0.67Ge_0.33. The electronic density of states and charge density analysis indicate that the FeMnP_1−xGa_x compounds have similar electronic structures to those of FeMnP_1−xGe_x. These results predict that FeMnP_1−xGa_x is a possible candidate refrigerant for room-temperature magnetic refrigeration.