One-dimensional magnetic order in the metal–organic framework \(Tb(HCOO)_3\)

Variable-temperature neutron scattering measurements, reverse Monte Carlo analysis and direct Monte Carlo simulation are used to characterise magnetic order in the metal–organic framework (MOF) \(Tb(HCOO)_3\) over the temperature range 100K to 1.6K = T\(_N\). The magnetic transition at T\(_N\) is shown to involve one-dimensional ferromagnetic ordering to a partially-ordered state related to the triangular Ising antiferromagnet and distinct from the canonical “partially-disordered antiferromagnet” model. In this phase, the direction of magnetisation of ferromagnetic chains tends to alternate between neighbouring chains but this alternation is frustrated and is not itself ordered. We suggest the existence of low-dimensional magnetic order in \(Tb(HCOO)_3\) is stabilised by the contrasting strength of inter- and intra-chain magnetic coupling, itself a consequence of the underlying MOF architecture. Our results demonstrate how MOFs may provide an attractive if as yet under-explored platform for the realisation and investigation of low-dimensional physics.