Bias Field Effects on Microwave Frequency Behavior of PZT/YIG Magnetoelectric Bilayer

Magnetoelectric behavior of a yttrium iron garnet (YIG)/zirconate titanate (PZT) magnetoelectric bilayer composite was studied over 1-7 GHz under different bias magnetic fields and electric fields by using a broadband air-gap microstrip with the PZT/YIG loaded in the air gap. Electrostatically induced ferrimagnetic resonance (FMR) frequency shifts of the YIG/PZT bilayer composite were studied. The FMR frequency shift was negligible at bias fields when the YIG was not saturated. After saturation, the FMR frequency increased nearly linearly from 15 MHz at a bias field of 100 Oe to 30 MHz at 1200 Oe and dropped suddenly at a field of 1300 Oe to about 20 MHz. This nonlinear bias magnetic held dependence was due to magnetic domain activities when the YIG was not saturated and due to the interference between the uniform mode and other magnetostatic spin waves after saturation. An electrostatically tunable band-reject filter device was demonstrated which has a peak attenuation of greater than 50 dB, 40 dB rejection band of 10 MHz, and pass band insertion loss of <5 dB at ~4.6 GHz.