Large reversible magnetocaloric effect in ferromagnetic semiconductor EuS

• We present magnetocaloric effect in ferromagnetic semiconductor EuS with TC~18 K.
• EuS shows large magnetic entropy change and adiabatic temperature change at TC.
• A high relative cooling power is also observed at TC even for a small field change.
• Large MCE in EuS is confirmed by both magnetization and specific heat measurements.
• EuS seems to be a potential magnetic refrigerant for liquefaction of hydrogen.

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 ΔTad~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, ΔTad 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.