Evidence for stress-mediated magnetoelectric coupling in multiferroic bilayer films from magnetic-field-dependent Raman scattering

We report the magnetic-field-dependent Raman scattering studies on Pb(Zr,Ti)O-3-CoFe2O4 bilayer multiferroic system. The phonon frequencies of the nanobilayers obviously change with magnetic field, which is absent in the single Pb(Zr,Ti)O-3 films. The magnetostriction of the CoFe2O4 layer generates stress mechanically transferred to the Pb(Zr,Ti)O-3 layer, resulting in the mode changes. The observed magnetic-field-induced softening of the soft mode in the Pb(Zr,Ti)O-3 layer bears a striking resemblance to direct magnetoelectric output in the bilayers, providing evidence for stress-mediated magnetoelectric coupling mechanism in the multiferroic bilayers.