Colossal Magnetoelectric Effect in Core-Shell Magnetoelectric Nanoparticles.

Magnetoelectric coefficient values of above 5 and 2 V cm Oe in 20 nm CoFeO-BaTiO and NiFeO-BaTiO core-shell magnetoelectric nanoparticles were demonstrated. These colossal values, compared to 0.1 V cm Oe commonly reported for the 0-3 system, are attributed to (i) the heterostructural lattice-matched interface between the magnetostrictive core and the piezoelectric shell, confirmed through transmission electron microscopy, and (ii) in situ scanning tunneling microscopy nanoprobe-based ME characterization.