Study of the magnetic transition and large magnetocaloric effect in DyCo₃B₂ compound

A single-phased DyCo₃B₂ compound has been prepared by an arc-melting method. The magnetic properties and magnetocaloric effect (MCE) have been studied by the magnetization and heat capacity measurements. The compound undergoes a magnetic Co-Co sublattice ordering at ∼150 K, and a second magnetic Dy-Dy sublattice ordering transition at 22 K. Magnetization and modified Arrott plots indicate that DyCo₃B₂ compound undergoes a second-order phase transition at ∼22 K. A large reversible magnetocaloric effect has been observed around Dy-Dy sublattice ordering temperature. The values of maximum magnetic entropy change (-ΔS _M^max) reach 7.4 and 15.1 J kg^-1 K^-1 for the field change of 2 and 7 T with no obvious hysteresis loss around 25 K; the corresponding values of maximum adiabatic temperature changes (ΔT _ad^max) are evaluated to be 6.4 and 13.8 K, respectively. The large reversible ΔS_M^max and ΔT _ad^max, as well as considerable relative cooling power, make DyCo₃B₂ compound a suitable candidate for low temperature magnetic refrigeration.