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

Abstract

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.