From: Development of a battery-free ultrasonically powered functional electrical stimulator for movement restoration after paralyzing spinal cord injury
Material
Coupling coefficient
Dielectric loss
Mechanical quality factor
PZT4
0.55
0.005
800
PZT5
0.74
0.02
70
PZT8
0.63
0.003
1100
BaTiO3
0.43
1300