Abstract

Strain engineering of the magnetic property is an important subject in the study of multiferroic materials.
Here we propose a multiferroic bilayer structure in which the magnetic remanence is controlled by the in-plane
strain of the top CFO (CoFe2O4) layer epitaxially constrained by the bottom Pb(Mg1/3Nb2/3)O3-PbTiO3 pi-ezoelectric substrate. We have shown that the room-temperature magnetic remanence (MR) of the 100-nm-thick
CFO layer is enhanced by 35.4% when an electric field of 10 kV/cm is applied. The MR value of our bilayer
structure was shown to be linearly proportional to the magnitude of the in-plane compressive strain which, in
turn, was proportional to the applied field strength. Synchrotron x-ray absorption near-edge structure study
supports a scenario of the cation-charge redistribution between Co2+ and Fe3+ ions under the condition of an
electric-field-induced in-plane compressive strain.