Piezoelectric properties and phase transitions of 〈001〉-oriented Pb(Zn_(1/3)Nb_(2/3))O_(3)-PbTiO_(3) single crystals

摘要

Electric-field-induced phase transitions and piezoelectric properties of 〈001〉-oriented Pb(Zn_(1/3)Nb_(2/3))O_(3)-xPbTiO_(3) single crystals for x=4.5 and 8 (PZN-4.5PT and PZN-8PT) have been investigated as a function of temperature. It was found that the piezoelectric properties and phase transitions for both crystals are strongly dependent on temperature. The measurements of polarization and strain as a function of unipolar electric field show that the field for the rhombohedral-tetragonal phase transition decreases linearly with temperature in the range between 25 and 105℃. Thus, raising the temperature can stabilize the tetragonal phase in 〈001〉-oriented PZN-PT crystals. Longitudinal piezoelectric constant d_(33) in the rhombohedral phase increases with temperature for both crystals; in PZN-4.5PT the slope itself increases significantly at temperatures over 60℃. In the field-induced tetragonal phase, there is little change in d_(33) for PZN-8PT within the temperature range investigated, while in PZN-4.5PT a slight increase of d_(33) with temperature was observed at temperatures above 80℃.