Stabilization by Si Substitution of the Pseudobinary Compound Gd2(Co3–xSix) with Magnetocaloric Properties around Room Temperature

We report the discovery of a new solid solution Gd2(Co3–xSix) with 0.29 x 2Ni3-type structure and correspond to the stabilization of “Gd2Co3” through silicon substitution. The structure of the member Gd2(Co2.53(3)Si0.47) was determined by X-ray diffraction on a single crystal. It crystallizes with the space group Cmce and cell parameters a = 5.3833(4), b = 9.5535(6), and c = 7.1233(5) Å. Co/Si mixing is observed on two crystallographic positions. All compounds studied in the solid solution present a ferrimagnetic order with a strong composition-dependent Curie temperature TC with 280 K TC –1 kg–1 for ΔH = 2 T, is interestingly tunable around room temperature over a temperature span of 60 K through only 4–5% of composition change.