Magnetic and magnetocaloric properties of the two-dimensional Ln2(phthalate)3(H2O) (Ln = Gd-Dy) framework series

The magnetic properties of a series of layered, two-dimensional Ln2(phth)3(H2O) materials (where Ln = Gd-Dy and phth = phthalate) metal–organic framework (MOF) materials have been examined to evaluate their potential as magnetocaloric materials. The Gd2(phth)3(H2O) material was found to exhibit the best performance of the series with a −ΔSmmax of 16.3 J kg−1 K−1 for a magnetic field change of 5–0 T. Although modest compared to other Gd-based magnetocaloric frameworks, this material was notable for exhibiting its peak entropy change at 4 K. This contrasts with the majority of Gd-based magnetocaloric materials whose performance is usually optimised at 2 K (or lower) and found to rapidly decrease with increasing temperature and is attributed to the stronger magnetic interactions present in this material.