Magnetoelectric coupling in the type-I multiferroic ScFeO3

We investigate the electronic structure and the ferroelectric properties of the recently discovered multiferroic ScFeO3 by means of ab initio calculations. The 3d manifold of Fe in the half-filled configuration naturally favors an antiferromagnetic ordering, with a theoretical estimate of the antiferromagnetic Néel temperature in good agreement with the experimental values. We find that the inversion symmetry breaking is driven by the off-centering of Sc atoms, which results in a large ferroelectric polarization of ∼105 μC/cm2. Surprisingly the ferroelectric polarization is sensitive to the local magnetization of the Fe atoms resulting in a large negative magnetoelectric interaction. This behavior is unexpected in type-I multiferroic materials because the magnetic and ferroelectric orders are of different origins.