Tailoring material properties by structure design–radially poled piezoelectric cylindrical tube

Abstract

In many applications such as hydrophone and ultrasonic transducers, materials with large piezoelectric anisotropy are preferred in order to suppress the interfering signals from lateral modes. It has been shown that piezoelectric anisotropy can be significantly improved by structure design. For instance, for a radially poled cylindrical tube, the effective transverse piezoelectric response can be tuned to zero. In this work, the effective piezoelectric responses of lead zirconate titanate (PZT) and lead magnesium niobate-lead titanate (PMN-PT) ceramic cylindrical tubes were studied. Large piezoelectric anisotropy with a high effective uniaxiai coefficient has been obtained for both materials. It has been shown that near zero effective d ₃₁ can be achieved for a PZT tube with a proper dimension ratio of r_o/R_o , where r_o , andR_o are inner and outer radii of the tube, respectively. While for a PMN-PT tube, the effective piezoelectric responses can be tuned by the ratio of r_o/R_O as well as the bias field because the induced piezoelectric coefficients d₃₃ and d ₃₁, and their ratio [d ₃₃/d₃₁] are all functions of the bias field.

Key Words:

• piezoelectric anisotropy
• relaxor ferroelectrics
• cylindrical tube structure.