Effect of Dy substitution on magnetic properties and magnetocaloric effects of Tb6Co1.67Si3 compounds

The magnetic and magnetocaloric properties of (Tbmagnetic properties, magnetic entropy change, refrigerant capacityProject supported by the National Basic Research Program of China (Grant No.~2006CB601101), the National Natural Science Foundation of China (Grant Nos.~50731007 and 10874223) and the Knowledge Innovation Project of the Chinese Academy of Sciences.7530S, 7550CThe magnetic and magnetocaloric properties of (Tbmagnetic properties, magnetic entropy change, refrigerant capacityProject supported by the National Basic Research Program of China (Grant No.~2006CB601101), the National Natural Science Foundation of China (Grant Nos.~50731007 and 10874223) and the Knowledge Innovation Project of the Chinese Academy of Sciences.7530S, 7550CThe magnetic and magnetocaloric properties of (Tbmagnetic properties, magnetic entropy change, refrigerant capacityProject supported by the National Basic Research Program of China (Grant No.~2006CB601101), the National Natural Science Foundation of China (Grant Nos.~50731007 and 10874223) and the Knowledge Innovation Project of the Chinese Academy of Sciences.7530S, 7550CThe magnetic and magnetocaloric properties of (Tb$_{1 - x}$Dy$_{x})_{6}$Co$_{1.67}$Si$_{3}$ ($0 \le x \le 0.8$) have been experimentally investigated. The compounds exhibit a Ce$_{6}$Ni$_{2}$Si$_{3}$-type hexagonal structure and undergo a second-order magnetic transition. The Curie temperature decreases from $\sim 187$~K to 142~K as the content of Dy grows from 0 to 0.8. The maximal magnetic entropy change, for a field change of 0--5~T, varies between $\sim 6.2$ and $\sim 7.4$~J/kg$\cdot$K, slightly decreasing when Dy is introduced. The substitution of Dy leads to a remarkable increase in refrigeration capacity (RC). A large RC value of $\sim 626$~J/kg is achieved for $x=0.4$ under a field change of 0--5~T.