Multiferroicity in Fe${}_4$Ta${}_2$O${}_9$

We report on the observation of multiple coupled magnetic and ferroelectric states in the Fe${}_4$Ta${}_2$O${}_9$ system, which appears to be the only genuine multiferroic in its material class. We suggest that the observed properties arise as a consequence of an effective reduction in the dimensionality of the magnetic lattice, with the magnetically active Fe${}^{2+}$ ions preferentially occupying a quasi 2D buckled honeycomb structure. A rich variety of coupled magnetic and ferroelectric states are seen which is similar to that observed in the distorted Kagome systems.