Electric field-induced magnetization switching in epitaxial columnar nanostructures

We present direct evidence for room-temperature magnetization reversal induced by an electric field in epitaxial ferroelectric BiFeO(3)-ferrimagnetic CoFe(2)O(4) columnar nanostructures. Piezoelectric force microscopy and magnetic force microscopy were used to locally image the coupled piezoelectric-magnetic switching. Quantitative analyses give a perpendicular magnetoelectric susceptibility of similar to 1.0 x 10(-2) G cm/V. The observed effect is due to the strong elastic coupling between the two ferroic constituents as the result of the three-dimensional heteroepitaxy.