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

Abstract The lattice parameters, magnetic phase transition, Curie temperature and magnetocaloric properties for the (Gd 1− x Tb x ) 5 Si 1.72 Ge 2.28 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 Gd 5 Si 1.72 Ge 2.28 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 T c . 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 (Gd 0.94 Tb 0.06 ) 5 Si 1.72 Ge 2.28 sample reaches 25.13 J kg −1  K −1 , much lager than that of pure Gd 5 Si 1.72 Ge 2.28 compound (13.73 J kg −1  K −1 at 247 K) in this work.