Large magnetic entropy change in TbAl2 and (Tb0.4Gd0.6)Al-2

Rare-earth intermetallic compounds (Tb1-xGdx)Al-2, have been successfully f abricated and characterized. Large magnetic entropy change, Delta S-M, was observed in these alloys. The maximum -Delta S-M(=14.3 J/kg K) is achieved in the TbAl2 alloy at its Curie temperature, T-C=105 K, with a 5 T magnetic field change. It is shown that the alloys are very soft magnetic alloys. T he magnetic entropy change is thus completely reversible in the whole tempe rature range of 80-180 K. An interesting feature in (Tb1-xGdx)Al-2 compound s is that the Curie temperature can be easily shifted by tuning the composi tion. These alloys, therefore, appear to be an attractive material candidat e for realizing the active magnetic regenerator magnetic refrigerator consi sting of eight stages, as suggested by K. A. Gschneidner, Jr. and V. K. Per charsky. [Rare Earth: Science, Technology, and Applications III, edited by R. G. Bautista, C. O. Bounds, T. W. Ellis, and B. T. Kilbourn (The Minerals , Metals and Materials Society, 1997), p. 209.] (C) 2000 American Institute of Physics. [S0003-6951(00)05735-1].