  The high frequency performance of strong piezoelectric materials like PZT
remains relatively less explored due to the assumption of large
dielectric/ferroelectric losses at GHz frequencies. Recently, the advent of
magnetoelectric technology as an on-chip route to excite magnetization dynamics
has provided the impetus to evaluate the electromechanical performance of PZT
at microwave frequencies. In this work, we demonstrate that HBARs fabricated
using Barium-doped PZT (BPZT) films can efficiently generate acoustic waves up
to 15 GHz. The ferroelectricity of BPZT endows added functionality to the
resonator in the form of voltage tunability of the electromechanical
performance. We extract the piezoelectric coefficient by numerically comparing
the performance of BPZT with the Mason model. The extracted piezoelectric
coefficient ~60 pm/V agrees well with reported values on thin film PZT measured
at low frequencies (<100 MHz). Our results suggest that with further
improvement in device design and material processing, BPZT resonators could
operate as large amplitude, tunable stress transducers at GHz frequencies.
