Magnetic entropy change of a rare earth garnet (Gd0.5Dy0.5)3(Ga0.875Fe0.125)5O12

The working refrigerant in magnetic refrigerators has been Gd3Ga5O12 (GGG) in the temperature range from 1 to 15 K. It has been shown that substitution of Ga for Fe in GGG can make entropy change large in high-temperature region. In order to increase the entropy change with small magnetic field, substitution of Gd for Dy is expected to be useful because of larger g-factor of Dy than Gd. The magnetization of (Gd0.5Dy0.5)(3)(Ga0.875Fe0.125)(5)O-12 (GDGIG) was measured and the entropy change was calculated. This compound had larger entropy change with small magnetic field than that without Dy, though the absolute entropy change at low temperatures with large applied field was smaller due to the ground state doublet of Dy. (C) 2003 Elsevier Science B.V. All rights reserved.