Low-Hysteresis Materials for Magnetic Refrigeration: Gd/sub 1-X/Er/sub X/Al sub 2

摘要

The series of ferromagnetic intermetallics Gd/sub 1-x/Er/sub x/Al sub 2 are candidate working materials for magnetic refrigeration because of their large moment, small anisotropy, and the fact that their Curie temperatures span the range 14 K to 164 K. We have measured the magnitude of the magnetic hysteresis as a function of temperature from 4 K to T/sub c/ for polycrystalline samples of these materials via ac magnetic susceptibility and magnetization hysteresis loops. We found, as expected, virtually no hysteresis in GdAl sub 2 , and more surprisingly, less than 3000 A/m hysteresis in ErAl sub 2 , and 2 x 10 exp 4 A/m in Gd sub 0 sub 5 Er sub 0 sub 5 Al sub 2 . Moreover, the hysteresis in Gd sub 0 sub 5 Er sub 0 sub 5 Al sub 2 was less than or equal to 100 A/m for T - T/sub c/ < 20 K. (ERA citation 09:000779)