The piezoelectric shear strain coefficient of 〈111〉-oriented Pb (Zn1/3Nb2/3)O3-PbTiO3 piezocrystals

The piezoelectric d15 coefficients of 〈111〉-oriented (1−x)Pb(Zn1/3Nb2/3)O3–xPbTiO3 single crystals for x=0.045 and x=0.08 (PZN-4.5%PT and PZN-8%PT) have been measured as functions of dc bias field and frequency using a Zygo laser interferometer system. High d15 values (∼5500 pC/N for PZN-4.5%PT and ∼7500 pC/N for PZN-8%PT) were obtained in the absence of dc bias. d15 decreased as the dc bias was increased. d15 was also found to decrease with increasing frequency, and this frequency dependence decreased at sufficiently large bias fields. Our results suggest that these 〈111〉-oriented crystals are promising materials for high performance shear transducers.