Investigation of dipolar defects in „1−x...Pb„Zn1/3Nb2/3...O3–xPbTiO3 single crystals using different poling methods

The temperature dependence of piezoelectric, pyroelectric, and dielectric properties have been measured for 001 and 111 oriented 0.92Pb Zn1/3Nb2/3 O3–0.08PbTiO3 PZN-8%PT and 0.955Pb Zn1/3Nb2/3 O3–0.045PbTiO3 PZN-4.5%PT single crystals poled by two different poling methods, i.e., room temperature RT poling and poling through field cooling FC . Compared with the RT poling case, some interesting features have been found in the FC poled 001 oriented crystal but not in the 111 oriented crystal. These features include the enhancement of piezoelectric properties, lowering of the transition temperature from rhombohedral to tetragonal phase, increasing the amplitude of the spontaneous polarization in the tetragonal phase region, and the decrease of the dielectric constants in the tetragonal phase. These results revealed that the dipolar defects in the crystals are formed between the B and O sites in the ABO3 perovskite structure. © 2007 American Institute of Physics. DOI: 10.1063/1.2401043