Dy(OH)₃: a paramagnetic magnetocaloric material for hydrogen liquefaction

The magnetic properties of a series of Ln(OH)(3) (where Ln = Gd-Er) coordination polymer materials have been examined to evaluate their potential as magnetocaloric materials. Dy(OH)(3) was found to exhibit an impressive magnetic entropy change of 33.4 J kg(-1) K-1 at 12 K for a magnetic field change of 5-0 T, based on magnetisation measurements. Further magnetic heat capacity analysis indicated a maximum adiabatic temperature change of 8.4 K at 22.7 K. The favourable magnetocaloric parameters obtained for Dy(OH)(3) demonstrated its effectiveness to act as a magnetic cooling material for hydrogen liquefaction, since the boiling point of hydrogen aligns well with the temperature for peak magnetocaloric performance of Dy(OH)(3) for high field changes.