Magneto-dielectric and magnetoelectric anisotropies of CoFe2O4/Bi5Ti3FeO15 bilayer composite heterostructural films

Abstract

Bilayer composite heterostructural films consisting of magnetic CoFe₂O₄ and multiferroic Bi₅Ti₃FeO₁₅ films were prepared by the chemical solution deposition method. Morphological, ferroelectric, piezoelectric, magnetic, magneto-dielectric and magnetoelectric properties were investigated for CoFe₂O₄/Bi₅Ti₃FeO₁₅ composite films. The magneto-dielectric and magnetoelectric effects are observed for the composite films, which is attributed to the enhanced interface coupling and mechanical strain transfer due to the small lattice mismatch between CoFe₂O₄ and Bi₅Ti₃FeO₁₅ film layers. Magneto-dielectric and magnetoelectric anisotropies were also observed for the composite films. Correspondingly, the in-plane and out-of-plane magnetoelectric voltage coefficients reach 57 mV cm⁻¹ Oe⁻¹ and 78.9 mV cm⁻¹ Oe⁻¹, respectively. Thus magneto-dielectric and magnetoelectric anisotropies originate from the magnetic anisotropy of CoFe₂O₄/Bi₅Ti₃FeO₁₅ composite films. The present work provides promising candidates for applications in magnetoelectric devices.