E-Field Tuned Rotation of Magnetic Anisotropy and Enhanced Microwave Performance in FeCoAlO/PZN–PT Multiferroic Composite Prepared by Composition Gradient Sputtering

An orthogonal biaxial magnetic anisotropy configuration was built in the FeCoAlO/PZN–PT multiferroic composite using two perpendicular uniaxial magnetic anisotropies (UMAs). One is stable and induced by composition gradient, and the other is electric field (E-field) dependent resulting from the magnetoelectric coupling between FeCoAlO ferromagnetic film and the PZN–PT ferroelectric substrate. As a result, the easy axis of a FeCoAlO soft magnetic film can be rotated nearly 90° by the E-field due to the competition between the two UMAs. The magnitude and direction of the ferromagnetic resonance frequency can be manipulated by E-field, and very high resonance frequency up to 9 GHz is achieved in this orthogonal biaxial multiferroic composite.