Study of the magnetic and magnetocaloric properties in RECoC (RE = Tb and Er) compounds

The crystal structure, magnetic phase transition and magnetocaloric effect (MCE) of TbCoC and ErCoC were systematically investigated. The compounds are crystallized in tetragonal YCoC-type structure (P4/mmm space group). TbCoC undergoes a second-order paramagnetic to ferromagnetic (PM-FM) magnetic phase transition around its Curie temperature TC = 22 K, whereas ErCoC has a field-induced first-order antiferromagnetic to ferromagnetic (AFM-FM) magnetic phase transition below Neel temperature TN = 10 K. Both compounds exhibit large reversible MCE accompanied with the magnetic phase transition. For ΔH = 0-5 T, the values of −ΔSMmax (maximum of magnetic entropy change) reach 16.5 and 18.7 J/kg K for TbCoC and ErCoC, respectively, the corresponding values of RCP (relative cooling power) are 470 and 371 J/kg.