Effect of Dy substitution on magnetic properties and magnetocaloric effects of Tb₆Co_1.67Si3 compounds

The magnetic and magnetocaloric properties of (Tb_{1 - x}Dy _x)₆Co_1.67Si₃ (0 ≤ x ≤ 0.8) have been experimentally investigated. The compounds exhibit a Ce ₆Ni₂Si₃-type hexagonal structure and undergo a second-order magnetic transition. The Curie temperature decreases from ∼ 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 ∼ 6.2 and ∼ 7.4 J/kgK, slightly decreasing when Dy is introduced. The substitution of Dy leads to a remarkable increase in refrigeration capacity (RC). A large RC value of ∼ 626 J/kg is achieved for x 0.4 under a field change of 0-5 T.