Colossal Linear Magnetoelectricity in Polar Magnet Fe₂Mo₃O₈

The linear magnetoelectric effect is an attractive phenomenon in condensed matters and provides indispensable technological functionalities. Here a colossal linear magnetoelectric effect with diagonal component alpha(33) reaching up to similar to 480 ps/m is reported in a polar magnet Fe2Mo3O8. This effect can persist in a broad range of magnetic field (similar to 20 T) and is orders of magnitude larger than reported values in literature. Such an exceptional experimental observation can be well reproduced by a theoretical model affirmatively unveiling the vital contributions from the exchange striction, while the sign difference of magnetocrystalline anisotropy can also be reasonably figured out.