Preparation And Properties Of Laminated Magnetoelectric Composite Thin Film

Magnetoelectric composite material is one of multiferroics, which shows a coupling magnetoelectric （ME） effect by the coupling magnetic-mechanical-electric interaction. In comparision with single phase magnetoelectrics, Magnetoelectric composite material exhibits a large ME coefficient, a high Curie temperature and Neer temperature. In recent years, it has drawn increasing interest due to their applications in multifunctional devices such as memorizer, sensor , transducer and so on.In this paper, two sets of bilayer multiferroic thin films consisting of CuFe₂O₄/BaTiO₃ and CuFe₂O₄/BiFeO₃ and a trilayer thin film BiFeO₃/NiFe₂O₄/BiFeO₃ were grown on Pt/Ti/SiO2/Si substrates by a pulsed-laser deposition. Phases were characterized by X-ray diffraction meter. Ferroelectric, dielectric, and magnetic property of the thin films were analysis using TF analyzer2000, Agilent 4294A and physical comprehensive performance system（PPMS）.For CuFe₂O₄/BaTiO₃ bilayer thin films samples, the grain size of the bilayer thin films samples are bigger than that of single thin film. Current density in single thin film BaTiO₃/Pt/Ti/SiO2/Si is about 10^-4 A/cm² at voltage of 10V, while it is about 10^-2 A/cm² in bilayer thin films. Moreover, leakage current density is affected by different orders of growing each constituent layer. Dielectric constants of the both bilayer thin films decrease with the increasing frequency in the range of 10²Hz-10⁶ Hz. The saturation magnetizations of these bilayer thin films are smaller than the one of pure single phase CuFe₂O₄ thin film. For CuFe₂O₄/BiFeO₃ bilayer thin films samples, the P-E loops of these heterostructure thin films show a rectangle shape with an applied voltage of 20V. Current density in single thin film BiFeO₃/Pt/Ti/SiO2/Si is about at voltage of 5V, while it is about in bilayer thin films. Moreover, leakage current density is affected by different orders of growing each constituent layer. Dielectric constants of the both bilayer thin films are steady in the range of Hz- Hz. The saturation magnetizations of these bilayer thin films are smaller than the one of pure single phase CuFe10 ?4 A/cm210 ?6 A/cm210 2106₂O₄ thin film. For BiFeO₃/NiFe₂O₄/BiFeO₃ trilayer thin films samples, saturation polarization are lower when the thickness of the NiFe₂O₄ thin film are bigger. Current density in （100/50/100）、（100/100/100）�'�（100/150/100） thin films is respectively about , and at voltage of 10V. Dielectric constants of the both trilayer thin films are steady in 10 ?7 A/cm210 ?8 A/cm210 ?9 A/cm2 the range of 10²Hz-10⁶Hz. The saturation magnetizations of these trilayer thin films are smaller than the one of pure single phase NiFe₂O₄ thin film and become bigger with the increasing of the NiFe₂O₄ film thickness. The intervener of the NiFe₂O₄ thin film makes the coercive field of the trilayer thin films samples smaller than the pure NiFe₂O₄ thin film.