A double-mode piezoelectric single-crystal ultrasonic micro-actuator

Ternary Pb(In
_1/2
Nb
_1/2
)O
₃
-Pb(Mg
_1/3
Nb
_2/3
)O
₃
-PbTiO
₃
(PIN-PMN-PT) single crystals with higher coercive field (E
_C
~9 kV/cm) and higher ferroelectric-transition temperature (T
_R-T
= 108°C) were grown, and correspondingly, a double-mode piezoelectric ultrasonic micro-actuator made of PIN-PMN-PT crystal brick (5 × 1.5 × 1.32 mm) and operated in the first longitudinal and the second bending modes was developed. The ferroelectric, dielectric, electromechanical, and resonance displacement properties of the micro-actuator were characterized for miniature linear piezo-motor applications. The longitudinal displacement of the actuator is ~0.11 μm (with an applied voltage of 5 V), which is comparable to that of a multilayer piezoelectric-ceramic actuator of the same size. This crystal micro-actuator was successfully used to drive a slider moving linearly.