Magnetic phase transition and magnetocaloric effect in (Gd1−xTbx)5Si1.72Ge2.28 compounds

The lattice parameters, magnetic phase transition, Curie temperature and magnetocaloric properties for the (Gd1−xTbx)5Si1.72Ge2.28 compounds with x = 0, 0.02, 0.04, 0.06, 0.08 and 0.10 have been investigated by X-ray powder diffraction and magnetization measurement. A small amount of the Tb substitution in Gd5Si1.72Ge2.28 compound can remain its first order magnetic-crystallographic transition and enhance its magnetic entropy change significantly, although have the negative influence on the compound Curie temperature Tc. The influence of the applied magnetic field on transition temperature also was discussed. The maximum magnetic entropy changes in the low magnetic field change of 2.0 T for the (Gd0.94Tb0.06)5Si1.72Ge2.28 sample reaches 25.13 J kg−1 K−1, much lager than that of pure Gd5Si1.72Ge2.28 compound (13.73 J kg−1 K−1 at 247 K) in this work.