The large cryogenic magnetocaloric effect of TbAl2 nanocapsules

TbAl2 nanocapsules with a core of TbAl2 compound and a shell of amorphous Al2O3 were synthesized by the arc-discharge technique using modified strategies. The TbAl2 nanocapsules display superparamagnetic properties between the blocking temperature of 70 K and the Curie temperature of 100 K. The absolute value of the change of magnetic entropy of the TbAl2 nanocapsules rapidly increases with decreasing temperature, reaching 23.83 J kg−1 K−1 at 7.5 K with a magnetic field change of 70 kOe.