ELECTROMECHANICAL PROPERTIES OF SOME PB(MG1/3NB2/3)O-3-PBTIO3-(BA,SR)TIO3 CERAMICS .1.

Compositional variation within the Pb(Mg1/3Nb2/3)O3-PbTiO3-(Ba,Sr)TiO3 (hereafter PMN-PT-BT,ST) ternary (6.4% less-than-or-equal-to PT% less-than-or-equal-to 14.1%, 1.25% less-than-or-equal-to BT,ST% less-than-or-equal-to 2.5%) results in major changes in induced strain and hysteresis. For the 1.25% BT family, the increase in strain correlates with an increase in T(max), while the dielectric loss is uncorrelated with hysteresis and strain. In addition, weak-field aging (which is not reset by application of field) shows little effect on strain and hysteresis for drive fields of > 0.2 MV/m. The vary narrow polarization-field loops (virgin curves nearly indistinguishable from subsequent cycles) show that weak-field permittivity is a good approximation to the high-field permittivity. Although these data clarify the frequency (T(max) is linearly dependent on the logarithm of the frequency) effect on weak-field dielectric behavior, they do not directly address the question of meaningful extrapolation of high-field strain with frequency. In particular, the question remains as to whether the high-field permittivity and strain are frequency dependent. In future papers we will address this question by a combination of measurement techniques as functions of frequency.