Direct measurement of magnetoelectric exchange in self-assembled epitaxial BiFeO3–CoFe2O4 nanocomposite thin films

We report the direct measurement of a magnetoelectric (ME) exchange between magnetostrictive CoFe2O4 nanopillars in a piezoelectric BiFeO3 matrix for single-layer nanocomposite epitaxial thin films grown on (001) SrTiO3 substrates with SrRuO3 bottom electrodes. The ME coefficient was measured by a magnetic cantilever method and had a maximum value of ∼20 mV/cm Oe. The films possessed saturation polarization (60 μC/cm2) and magnetization (410 emu/cc) properties equivalent to bulk values, with typical hysteresis loops.