Magnetic phase transitions and magnetocaloric effect of MnCoGe1−xSix

Here a cheaper alternative magnetic refrigeration material using MnCoGe1−xSix (x=0, 0.1, 0.3, and 0.5) alloys were investigated. The polycrystalline MnCoGe1−xSix alloys were prepared by arc-melting followed by annealing at 1123 K for 72 h. At a 0.5 at% Si substitution, the Curie temperatures increased by 10% to 374 K, the magnetic entropy change (|ΔSM|) values decreased by 32% to 2.1 J kg−1 K−1 in an applied field from 0 to 2 T and by 24% to 4.4 J kg−1 K−1 in an applied field from 0 to 5 T. However, the refrigeration capacity (RCFWHM) of this MnCoGe0.5Si0.5 alloy improved by 27% to 282 J kg−1 and the operation temperature range (δTFWHM) improved by 92% to 96 K in an applied field at 5 T. The MnCoGe0.5Si0.5 alloy can compete with some of the MCE properties of the MnCo0.95Ni0.05Ge, LaFe11Al2C0.5, (Fe85Co5Cr10)91Zr7B2, and even the Gd5Si2Ge2 alloys. The broad operation temperature range (96 K) at a higher Curie temperature (374 K) suggests that the MnCoGe0.5Si0.5 alloy can become a cheaper alternative MCE material (costing 70% less than a MnCoGe alloy).