Glass formation, magnetic properties and magnetocaloric effect of ternary Ho–Al–Co bulk metallic glass

A ternary Ho–Al–Co system with high glass-forming ability (GFA) was developed and fully glassy rods with diameters up to 1 cm can be produced for the best glass former of Ho55Al27.5Co17.5 alloy. The thermal stability and low-temperature magnetic properties of the Ho55Al27.5Co17.5 bulk metallic glass (BMG) were studied. The magnetic transition temperature of this alloy is ∼14 K as determined by the thermomagnetic measurement. Two indicators, i.e. isothermal magnetic entropy change (ΔSM) and the relative cooling power (RCP), were adopted to evaluate the magnetocaloric effect (MCE) of the alloy under a low magnetic field up to 2 T, which can be generated by permanent magnets. The values of |ΔSM| and RCP are 7.98 J kg−1 K−1 and 191.5 J kg−1, respectively. The Ho55Al27.5Co17.5 BMG with good MCE and high GFA provides an attractive candidate for magnetic refrigeration applications, like hydrogen liquefaction and storage.

► A ternary Ho–Al–Co BMG system with high glass-forming ability was developed.
► Fully glassy rods of Ho55Al27.5Co17.5 alloy were produced up to 1 cm in diameter.
► The thermal stability and magnetic properties of the BMG were evaluated.
► The BMG exhibits good magnetocaloric effect under a low magnetic field up to 2 T.