BPZT HBARs for Magnetoelastic Stress Generation at GHz Frequencies

Area of Science:

• Materials Science
• Electrical Engineering
• Acoustics

Background:

• High-frequency performance of piezoelectric materials like lead zirconate titanate (PZT) is underexplored due to assumed losses.
• Magnetoelectric technology now enables evaluation of PZT electromechanical performance at microwave frequencies.

Purpose of the Study:

• To evaluate the high-frequency electromechanical performance of barium-doped PZT (BPZT) films.
• To demonstrate the potential of BPZT in GHz acoustic wave generation and tunable stress transduction.

Main Methods:

• Fabrication of high-overtone bulk acoustic resonators using BPZT films.
• Numerical comparison of BPZT resonator performance with the Mason model to extract the piezoelectric coefficient.

Main Results:

• BPZT resonators efficiently generate acoustic waves up to 15 GHz.
• The ferroelectricity of BPZT allows for voltage tunability of electromechanical performance.
• Extracted piezoelectric coefficient of ~60 pm/V agrees with low-frequency thin-film PZT values.

Conclusions:

• BPZT resonators are effective for GHz acoustic wave generation.
• Voltage tunability offers added functionality for electromechanical applications.
• Further optimization could enable BPZT resonators as tunable stress transducers at GHz frequencies.