Coloring problem and magnetocaloric effect of Gd3Co2.2Si1.8

The Gd3Co2.2Si1.8 compound was synthesized by arc melting the constituent elements and subsequent annealing at 1070K for 120h. It adopts the Dy3Co2.2Si1.8-type structure with the space group Cmcm and the unit cell parameters of a=4.1176(7)Å, b=10.305(2)Å, c=12.778(2)Å and V=542.2(2)Å3. The Co and Si atoms preferentially occupy the 8f and 4a/4c sites, respectively. The atomic electronegativity and electron density at a given site determine its site occupation, according to the analysis of the electronic structure. Gd3Co2.2Si1.8 orders ferromagnetically with the Curie temperature of 172K. The isothermal magnetic entropy change, −ΔSm, reaches the maximum value of 7.09J/kgK at 170K for a field change of 0–50kOe.