Magnetocaloric effect of Gd₅Si₂Ge₂ alloys in low magnetic field

摘要

The magnetocaloric effect of Gd₅Si₂Ge₂ alloys under heat treatment conditions are investigated in low magnetic fields. The magnetocaloric effect (MCE) is studied by measuring magnetic entropy change (ΔS _M) and adiabatic temperature change (ΔT _ad) in a magnetic field of 1·5 T using a vibrating sample magnetometer (VSM) and a home-made magnetocaloric effect measuring apparatus, respectively. The maximum ΔS _M of the alloys increases by 200% from 4·38 to 13·32 J kg−1 K−1, the maximum ·T _ad increases by 105% from 1·9 to 3·9 K when compared to the as-cast due to the homogeneous composition distribution and microstructure, while the magnetic ordering temperature is slightly reduced. These results indicate that the annealed Gd₅Si₂Ge₂ compounds are promising as high-performance magnetic refrigerants working room temperature in relatively low magnetic fields.