Structural and magnetic properties of Dy1−xNdxCo4Ga compounds

The structural and magnetic properties of Dy1−xNdxCo4Ga compounds with x = 0, 0.2, 0.4, 0.6, 0.8 and 1.0, have been investigated by X-ray diffraction and magnetic measurements. Powder X-ray diffraction analysis revealed that the Dy1−xNdxCo4Ga compounds form in single phase with a hexagonal CaCu5-type structure (space group P6/mmm) for all the composition range. The substitution of Dy by Nd in the compound increases its lattice parameters a, c and cell volume V, but decreases the rare earth 4f-sublattice moment and reduces the 3d-3d exchange interaction. As result, the Curie temperatures of Dy1−xNdxCo4Ga decreases from 498 K for x = 0 to 410 K for x = 1.0. The compensation temperatures Tcomp decrease from 286 K for x = 0 to 178 K for x = 0.2, and even lower than 100 K for the samples with x = 0.4 to x = 1. The spin-reorientation transitions decreases from 403 K for x = 0 to 303 K for x = 1.0. The maximum magnetic entropy change (−ΔSM) are 0.91 J kg−1 K−1 at 301 K for the spin-reorientation (SR) transition and 0.62 J kg−1 K−1 at 405 K for FM-PM transition in the compound NdCo4Ga in the magnetic field change of 1.5 T.