Coexistence ofFerroelectricity and Antiferromagnetismin Manganese-Based Hybrid Organic–Inorganic Perovskites

Hybrid organic–inorganic perovskites (HOIPs) are attractive for the application of functional materials that provide multiple degrees of freedom for ferro orders. By employing first-principles calculations, we propose the coexistence of ferroelectric and antiferromagnetic orders in AMnX₃-type hybrid organic–inorganic perovskites (HOIPs) (A = NH₄⁺, CH₃NH₃⁺, and CH₃CH₂NH₃⁺, X= Cl, Br, I), which are distinguished from conventional inorganic perovskites, where the magnetic and ferroelectric orders often suppress each other. On the one hand, we show that the antiferroelectric magnetic order originates from the Mn sublattice. On the other hand, the spontaneous ferroelectric order in AMnX₃-type HOIPs may have different origins depending on the size of the A-site organic molecules and are strongly affected by their interaction with the inorganic lattice frame. This work provides a promising strategy for subsequent investigations and applications of multiferroic materials.