Large reversible magnetocaloric effect in ferromagnetic semiconductor EuS

We present the large reversible magnetocaloric effect (MCE) of the ferromagnetic semiconductor EuS, which shows a maximum magnetic entropy change of -ΔSmmax~37 J kg^-1 K^-1, an adiabatic temperature change of ΔT_ad~10.4 K and a relative cooling power of RCP~782 J kg^-1 at 18.5 K for a magnetic field change ΔH=5 T. Particularly, the large MCE is isotropic and without hysteresis loss, even for a magnetic field change of 2 T the values of -ΔSmmax, ΔT_ad and RCP reach as high as 22 J kg^-1 K^-1, 7.5 K and 284 J kg^-1, respectively. These results indicate that EuS has excellent refrigeration performance at the temperatures near 20 K, and thus can be considered as the potential magnetic refrigerant material for liquefaction of hydrogen.