Magnetic‐Field Controllable Displacement‐Type Ferroelectricity Driven by Off‐Center Fe2+ Ions in CaFe3Ti4O12 Perovskite

Abstract Displacement‐type ferroelectrics usually exclude magnetic d ‐electron contribution. Applying a magnetic field thus can little change the electric polarization. Herein, a magnetic ionic driven displacement‐type perovskite ferroelectric CaFe 3 Ti 4 O 12 is reported. In this compound, magnetic Fe 2+ ions contribute to both ferroelectric and antiferromagnetic orders respectively at T C ≈107 and T N ≈ 3.1 K, resulting in coupled electric and magnetic domains. A moderate magnetic field can induce a metamagnetic transition toward ferromagnetic correlations. External magnetic fields can thus readily tune the magnetic and the joint ferroelectric domains, giving rise to exceptional magnetic‐field controllable displacement‐type polarization with a large magnetoelectric (ME) coupling coefficient. This study opens up a new avenue to find unprecedented ME effects in displacement‐type ferroelectrics for numerous applications.