Giant Electric Field Tuning of Magnetic Properties in Multiferroic Ferrite/Ferroelectric Heterostructures

摘要

Multiferroic heterostructures of Fe_3O_4/PZT (lead zirconium titanate), Fe_3O_4/ PMN-PT (lead magnesium niobate-lead titanate) and Fe_3O_4/PZN-PT (lead zinc niobate-lead titanate) are prepared by spin-spray depositing Fe_3O_4 ferrite film on ferroelectric PZT, PMN-PT and PZN-PT substrates at a low temperature of 90 C. Strong magnetoelectric coupling (ME) and giant microwave tunability are demonstrated by a electrostatic field induced magnetic anisotropic field change in these heterostructures. A high electrostatically tunable ferromagnetic resonance (FMR) field shift up to 600 Oe, corresponding to a large microwave ME coefficient of 67 Oe cm kV~(-1), is observed in Fe_3O_4/PMN-PT heterostructures. A record-high electrostatically tunable FMR field range of 860 Oe with a linewidth of 330-380 Oe is demonstrated in Fe_3O_4/PZN-PT heterostructure, corresponding to a ME coefficient of 108 Oe cm kV~(-1). Static ME interaction is also investigated and a maximum electric field induced squareness ratio change of 40% is observed in Fe_3O_4/PZN-PT. In addition, a new concept that the external magnetic orientation and the electric field cooperate to determine microwave magnetic tunability is brought forth to significantly enhance the microwave tunable range up to 1000 Oe. These low temperature synthesized multiferroic heterostructures exhibiting giant electrostatically induced tunable magnetic resonance field at microwave frequencies provide great opportunities for electrostatically tunable microwave multiferroic devices.