  The magnetic susceptibility and isothermal magnetization for GdF3 were
measured, and the isothermal entropy change was evaluated up to 9 T. Combining
the large isotropic spin of Gd3+, the dense structure and the weak
ferromagnetic interaction, an extremely large -(delta)Sm for GdF3 was observed
up to 528 mJ cm-3 K-1 for (delta)H = 9 T, proving itself to be the best
cryogenic magnetic coolant ever.
