Reversible Tuning of Magnetization in a Ferromagnetic Ruddlesden–Popper‐Type Manganite by Electrochemical Fluoride‐Ion Intercalation

Electrical tuning of materials' magnetic properties is of great technological interest, and in particular reversible on/off switching of ferromagnetism can enable various new applications. Reversible magnetization tuning in the ferromagnetic Ruddlesden–Popper manganite La₂₋₂ₓSr₁₊₂ₓMn₂O₇ by electrochemical fluoride‐ion (de)intercalation in an all‐solid‐state system is demonstrated for the first time. A 67% change in relative magnetization is observed with a low operating potential of <1 V, negligible capacity fading, and high Coulombic efficiency. This system offers a high magnetoelectric voltage coefficient, indicating high energy efficiency. This method can also be extended to tune other materials' properties in various perovskite‐related materials.