Magnetic properties and magnetocaloric effect in the aluminide RENiAl2 (REÂ =Â Ho and Er) compounds

Two single-phased aluminide RENiAl2 (RE = Ho and Er) compounds have been synthesized by an arc-melting method. The magnetic properties and magnetocaloric effect (MCE) of HoNiAl2 and ErNiAl2 have been studied by magnetization measurements. A second-order paramagnetic (PM) to ferromagnetic (FM) phase transition together with a considerable reversible MCE were observed around the Curie temperature TC ∼7.5 K and 5.0 K for HoNiAl2 and ErNiAl2, respectively. Under the magnetic field change (ΔH) of 0-5 T, the maximal values of magnetic entropy change, refrigerant capacity and relative cooling power are 14.0 J/kg K, 171 J/kg, 213 J/kg for HoNiAl2 and 21.2 J/kg K, 267 J/kg, 357 J/kg for ErNiAl2, respectively.