Characterization of flux-grown PZN-PT single crystals for high-performance piezo devices

Relaxor ferroelectric Pb(Zn
_1/3
Nb
_2/3
)O
₃
-xPbTiO
₃
(PZN-PT) and Pb(Mg
_1/3
Nb
_2/3
)O
₃
-PbTiO
₃
(PMN-PT) single crystals are the potential candidates for future high-performance piezoelectric devices due to their exceptionally high dielectric and piezoelectric properties. Characterization on flux-grown PZN-PT single crystals of different orientations revealed that PZN-(6-7)%PT single crystals show good homogeneity in dielectric and electromechanical properties and composition. When poled in [001] direction, these crystals exhibit high longitudinal-mode properties with dielectric constant (K
^T
)ap7000, piezoelectric coefficients (d
₃₃
)ap2800 pC/N, and electromechanical coupling factors (k
₃₃
)ges0.92. For [011]-cut crystals, optimally poled PZN-7%PT single crystal exhibits very high transverse-mode dielectric and piezoelectric properties with K
^T
ges5000, d
₃₂
ap-3800 pC/N and k
₃₂
ges0.90. [011]-poled PZN-6%PT has d
₃₂
ap-3000 pC/N and comparable k
₃₂
and K
^T
values. In comparison with melt-grown PMN-PT single crystals, flux-grown PZN-PT single crystals show good compositional homogeneity, superior and consistent dielectric and electromechanical properties, and higher depolarization temperatures (Tup).