Room‐Temperature Magnetoelectric Coupling in Atomically Thin ε‐Fe ₂ O ₃

Abstract 2D multiferroics with magnetoelectric coupling combine the magnetic order and electric polarization in a single phase, providing a cornerstone for constructing high‐density information storages and low‐energy‐consumption spintronic devices. The strong interactions between various order parameters are crucial for realizing such multifunctional applications, nevertheless, this criterion is rarely met in classical 2D materials at room‐temperature. Here an ingenious space‐confined chemical vapor deposition strategy is designed to synthesize atomically thin non‐layered ε‐Fe ₂ O ₃ single crystals and disclose the room‐temperature long‐range ferrimagnetic order. Interestingly, the strong ferroelectricity and its switching behavior are unambiguously discovered in atomically thin ε‐Fe ₂ O ₃ , accompanied with an anomalous thickness‐dependent coercive voltage. More significantly, the robust room‐temperature magnetoelectric coupling is uncovered by controlling the magnetism with electric field and verifies the multiferroic feature of atomically thin ε‐Fe ₂ O ₃ . This work not only represents a substantial leap in terms of the controllable synthesis of 2D multiferroics with robust magnetoelectric coupling, but also provides a crucial step toward the practical applications in low‐energy‐consumption electric‐writing/magnetic‐reading devices.