Large Magnetocaloric Effect of PrNi Compound at Liquid-hydrogen Temperatures

In the work, polycrystalline PrNi compound was synthesized by the arc-melting method. The Curie temperature (T
C
) is determined to be 21 K according to the maximum absolute value of first derivative of magnetization. The slope of the Arrott plots is positive around phase transition temperature, indicating of the SOPT characteristic. The magnetic entropy change (-ΔS
M
) was obtained from the isothermal magnetization data based on the Maxwell’s relationship. The maximum value of -ΔS
M
is calculated to be 7.4 and 13.0 J/kg K for the magnetic field changes of 0-2 T and 0-5 T, respectively. The large MCE around 21 K with SOPT feature indicates that PrNi is a possible candidate in the application of magnetic refrigeration for hydrogen liquefaction.