Dynamic Electromechanical Characterization of Ferroelectrics at Cryogenic Temperatures

Abstract

Ferroelectrics are utilized in a myriad of technological applications including vibration damping due to their inherent electromechanical coupling. Through the domain structure in ferroelectric ceramics, the high stiffness material can also exhibit high damping. The combination of high stiffness and high damping is an elusive property in engineering materials. Nonetheless, high stiffness and damping materials would be useful in load-bearing structures that are subjected to vibrations, in particular in space structures. Applying an electric field to ferroelectrics has shown promise for achieving this desirable combination of properties. However, there is limited knowledge on how the dynamic electromechanical properties of ferroelectrics change in a space environment (in particular at cryogenic temperatures), which has limited the exploitation of this ferroelectric property in space structures. This is due in part to the lack of experimental methods to measure such properties. To close this gap, cryogenic broadband electromechanical spectroscopy (CBES) was developed to measure the dynamic electromechanical response of ferroelectrics, viz. lead zirconate titanate, at cryogenic temperatures. In particular, CBES is used to measure simultaneously, for the first time, the dynamic stiffness, loss tangent, and electric displacement response of ferroelectrics subjected to large electric fields at cryogenic temperatures as low as 34 K. Measurements reveal a decrease in the amount of electric field-induced domain switching (and corresponding thermodynamic driving force) and the resulting mechanical damping. This points toward the need to develop alternative material compositions and microstructures for utilizing domain switching-induced damping in space structures.