Large magnetocaloric effect in TbCo3B2 compound

A single-phased TbCo3B2 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. A large reversible magnetocaloric effect has been observed accompanied by a second-order phase transition at around Tb–Tb sublattice ordering temperature. The values of maximum magnetic entropy change (−ΔSMmax) reach 4.9 and 10.3 J kg−1 K−1 for the field change of 2 and 7 T with no obvious hysteresis loss around 30 K, respectively. The corresponding maximum adiabatic temperature changes (ΔTadmax) are evaluated to be 4.0 and 8.6 K. The magnetic transition and the origin of large MCE in TbCo3B2 were discussed.

Research highlights▶ The magnetic properties and magnetocaloric effect (MCE) in TbCo3B2 have been studied by the magnetization and heat capacity measurements. ▶ A large reversible magnetocaloric effect has been observed in TbCo3B2 accompanied by a second-order phase transition at around Tb–Tb sublattice ordering temperature. ▶ Compared with some first order magnetic transition materials, the present TbCo3B2 compound and some second order magnetic transition materials have high reversible MCE which makes them to be competitive materials for active magnetic-refrigeration application. ▶ The present results may give some clue for searching new materials with large MCE.