Multiferroicity Engineered by Co2+ Substitution in Hybrid Ferroelectrics

Abstract

Achieving coexisting magnetic and electric orders in a single material presents a formidable barrier to developing advanced multiferroics. Here, we overcome this challenge in a soft hybrid system by partially substituting Pb²⁺ with magnetic Co²⁺ in the ferroelectric lattice of TMAPbI₃ (TMA⁺ = tetramethylammonium). The resulting TMA_1-xPb_1-xCo_xI_3-x (x = 0.03–0.10) alloy hybrids, synthesized via mechanochemistry, retain ferroelectricity below 183 K while simultaneously acquiring Co²⁺-tunable glassy magnetic ordering at 2–10 K. This work validates the incorporation of magnetic ions into hybrid ferroelectrics as a general and powerful approach to creating multiferroics, opening a direct pathway for engineering coupled functionalities in metal halide hybrids.