| This thesis explores the dielectric, piezoelectric, and electrostrictive properties of a number of relaxor ferroelectric-based solid solution systems. The components of these solid solution systems have a variety of characteristics ranging from normal- to relaxor- to anti-ferroelectric. Some of the relaxor end-members investigated were Pb(In1/2Nb1/2)O3 [PIN], Pb(In1/2Ta1/2)O3 [PIT], Pb(Sc 1/2Nb1/2)O3 [PSN], Pb(Ni1/3Nb 2/3)O3 [PNN], Pb(Mg1/3Nb2/3)O 3 [PMN], and Pb(Zn1/3Nb2/3)O3 [PZN].;Several of these systems have Curie temperatures [Tc] that are among the highest known for MPB compositions. Some examples are PIN-0.38PT with a Tc of 319°C, PIT-0.38PT with a Tc of 248°C, and PSN 0.42PT with a Tc of 254°C. While these are slightly lower that those of typically found in PZT, the temperature dependence of the piezoelectric properties was found to be minimal. The electromechanical coupling coefficients were largely unchanged upon heating to as high as 150°C. This is approximately equal to the Tc of PMN-PT and PZN-PT and significantly exceeds the generally accepted maximum operating temperature for these materials.;Many of the materials studied were found to have very large electromechanical coupling factors and produce extraordinarily high field-induced strains. Both PSN-0.42PT and PNN-0.15PZ-0.34PT were found to produce strain levels of ∼0.30% under unipolar drive with limited hysteresis. Peak-to-peak strain levels of as much as 0.60% were possible under bipolar drive conditions. Both of these MPB compositions had very large piezoelectric properties, with the slightly larger values of d33 = 810pC/N, kp = 0.69, kt = 0.56, and k33 = 0.80 occurring in PNN-PZ-PT.;Each of the MPB compositions studied has features that can be exploited for specific applications. The combination of high Tc and coercive field found in both PIN-PT and Bi(Ni1/2T1/2)O3 -PT should allow these materials to be used at high drive levels and/or at high temperatures. The high strain, low hysteresis, and large piezoelectric properties found in PSN-PT and PNN-PZ-PT indicate that these could be excellent actuators as well as ultrasound transducers. Other materials such as PIN-PbZrO 3, have large anisotropy in the electromechanical coupling coefficients (k33 = 0.29 and k31 = 0.04) that leads to large hydrostatic piezoelectric figures-of-merit. The 1-x(PSN-PT)-x(PZN-PT) pseudo binary system was also successfully used to show that relaxor-based ternary systems could be used to combine the features of two MPB compositions, in this case for example, the high Tc and temperature stability of PSN-PT with the low cost and easy crystal growth of PZN-PT.;Macro- to micro-domain transitions occurred in many of the relaxor-relaxor solid solutions including both the PIN-PMN and PSN-PMN solid solutions. Large values of the electrostrictive coefficient similar to that of pure PMN were also measured. The PIN-PMN system exhibited particularly low levels of strain hysteresis. The ability to compositionally tune the properties of these systems will be advantageous in the design of room temperature IR sensors, micropositioners, and capacitors.;The PIN-PNN system was determined to have large values of the pyroelectric coefficient at low temperatures. With appropriate compositional tuning the pyroelectric coefficient can be maximized at 77K making this an excellent candidate for cooled pyroelectric imaging. |
