Dy(OH)3: A Paramagnetic Magnetocaloric 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 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.