Reversible modulation of magnetic anisotropy and coercivity triggered by external bias voltage in CoFe2O4/Pb(Mg1/3Nb2/3)O3–PbTiO3 multiferroic heterostructures

Abstract

Multiferroic materials have been studied extensively in recent years as their abundant fundamental physics and technological applications. As we known, although multi order of ferroics can exist in one compound, these materials usually exhibit weak magnetoelectric coupling and low Curie temperature. Therefore multiferroic heterostructure is employed as a solution for the enhanced magnetoelectric response and its wide temperature survival. In this study, the magnetic property of, especially under electric field, multiferroic heterostructure CoFe2O4/0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 (CFO/PMN-PT) has been comprehensively explored. By the magneto-optical Kerr effect measurement, it is found that the magnetic properties of CoFe2O4 (CFO) thin film is tunable and reversible by the external electric field as the piezoelectric nature of 0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 (PMN-PT). The in-plane magnetic anisotropy of CFO film is observed distinctly, and the difference value of the coercive field with magnetic field along PMN-PT [0 0 1] and [1 1¯ 0] changes from 608 to 841 Oe by the electric field. The strain dependence of the change of coercive field has been demonstrated by both experimental and theoretical study, revealing the coupling mechanism in the heterostructure. Our result shows that the multiferroic heterostructure CFO/PMN-PT exhibits the application of electric field controlled exchange bias and the electric field assisted data storage device.