Magnetocaloric Effect In Gd5-Xdyxsi4 Compounds

The compound Gd5Si4 is known as a candidate for magnetic refrigerant in the vicinity of room temperature. Since Dy ion has a smaller de Gennes factor and larger angular momentum than those of Gd ion, it is expected that the Curie temperature of 335 K and magnetocaloric effect for Gd5Si4 will be decreased and increased, respectively, by Dy substitution for Gd of Gd5Si4. In this study, Gd5-xDyxSi4 with x=0, 0.5, 1, and 2 have been prepared, and the magnetocaloric effects together with the magnetic properties have been measured in a magnetic field up to about 2 T. Maximum temperature rise of 3.1 K is obtained for Gd5Si4 at the Curie temperature of 335 K and in a magnetic field of 1.92 T. The Dy-substituted samples, which have a lower Curie temperature than that of Gd5Si4, have shown almost the same magnetocaloric effect as that of Gd5Si4. The data are discussed on the basis of calculation of magnetic entropy for Gd5Si4. (C) 2006 American Institute of Physics.