Colossal linear magnetoelectricity in polar magnet Fe2Mo3O8

Linear magnetoelectric effect is an attractive phenomenon in condensed matters and provides indispensable technological functionalities. Here a colossal linear magnetoelectric effect with diagonal component alfa_33 reaching up to ~480 ps/m is reported in a polar magnet Fe2Mo3O8, and this effect can persist in a broad range of magnetic field (~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.