关键词: Gd₆Co_1.67Si_2.5Ge_0.5 compound, magnetocaloric effect, refrigerant capacity

Abstract: Magnetic entropy change ($\Delta S_{\rm M})$ and refrigerant capacity ($RC$) of Ce$_{6}$Ni$_{2}$Si$_{3}$-type Gd$_{6}$Co$_{1.67}$Si$_{2.5}$Ge$_{0.5}$ compounds have been investigated. The  Gd$_{6}$Co$_{1.67}$Si$_{2.5}$Ge$_{0.5}$ undergoes a reversible second-order phase transition at the Curie temperature $T_{\rm C} = 296$ K. The high saturation magnetization leads to a large $\Delta S_{\rm M}$ and the maximal  value of $\Delta S_{\rm M}$ is found to be 5.9 J/kg$\cdot$K around $T_{\rm C}$ for a field change of 0--5 T. A broad distribution of the $\Delta S_{\rm M}$ peak is observed and the full width at half maximum of the $\Delta S_{\rm M}$ peak is about 101~K under a magnetic field of 5 T. The large $RC$ is found around $T_{\rm C}$ and its value is 424 J/kg.

Key words: Gd₆Co_1.67Si_2.5Ge_0.5 compound, magnetocaloric effect, refrigerant capacity