Low Working Temperature of Erbium Orthophosphate ErPO4 with Large Magnetocaloric Effect

Erbium orthophosphate ErPO 4 was successfully prepared. The XRD pattern analyses have proved that the ErPO 4 crystallizes in the tetragonal structure (I4 1 /amd). Under a magnetic field of 50 kOe, the magnetic entropy change (− Δ S M ) reaches 23.78 J/kg K at 2.6 K for ErPO 4 . The value of the relative cooling power is 475 J/kg. The lowest temperature and the large MCE have inferred that ErPO 4 is a potential candidate for sub-kelvin magnetic refrigeration applications.