Orientation effects, hydrostatic response, and figures of merit in 2–2-type composites based on relaxor-ferroelectric single crystals

Abstract

The article reports new results on the hydrostatic performance of laminar piezo-active composites based on domain-engineered relaxor-ferroelectric single crystals (SCs) with the perovskite-type structure. Layers of the composites are either single-crystal poled along [011] (where rotations of the main crystallographic axes around two co-ordinate axes are considered) or porous polymer, with aligned spheroidal pores. These composites are described by 2–2–0 connectivity. An influence of the rotation of the main crystallographic axes and porosity is analyzed, and maxima of the hydrostatic piezoelectric coefficient $d_h^{*},$ figure of merit $d_h^{*}$ $g_h^{*},$ and electromechanical coupling factor $k_h^{*},$ of the composites are found as functions of a few parameters. New diagrams are built to show regions of the large $d_h^{*}$ (over 1000 pC/N) at variations of two rotation angles in the single-crystal layers. Large values of the hydrostatic figure of merit $d_h^{*}$ $g_h^{*}$ ∼ (10⁻¹⁰ – 10⁻⁹) Pa⁻¹ and electromechanical coupling factor $k_h^{*}$ are achieved in specific volume-fraction and rotation-angle ranges. These and other large values of the hydrostatic parameters of the studied 2–2-type composites are important for effective hydroacoustic applications.

Keywords:

• Piezo-active composite
• domain-engineered single crystal
• hydrostatic parameters
• figure of merit
• electromechanical coupling factor

Acknowledgments

The authors would like to thank Prof. Dr. A. E. Panich and Prof. Dr. I. A. Parinov (Southern Federal University, Russia) and Prof. Dr. P. Bisegna (University of Rome Tor Vergata, Italy) for their interest in the performance of advanced piezo-active composites.

Additional information

Funding

Research was financially supported by Southern Federal University, grant No. VnGr-07/2020-04-IM (Ministry of Science and Higher Education of the Russian Federation).