Ultrahigh measured electrostrain in polycrystalline bulk piezoceramics: Role of mechanically relaxed grains

TL;DR

This study reveals that ultrahigh electrostrain in thin polycrystalline piezoceramics results from reduced mechanical clamping between grains, allowing greater ferroelastic domain switching, which could improve piezoelectric device performance.

Contribution

It demonstrates the correlation between grain decoupling and enhanced electrostrain in thin polycrystalline piezoceramics, highlighting a mechanism for improved piezoelectric response.

Findings

Electrostrain increases dramatically in thin ceramics (~200 microns)

Reduced grain clamping enables more ferroelastic domain switching

Mechanically relaxed grains are key to ultrahigh electrostrain

Abstract

Recently we found that when conventional bulk polycrystalline piezoceramics discs (~ 10 mm diameter) are thinned down to thickness ~ 200 microns or below, the measured unipolar electrostrain (UES) values increased phenomenally (arXiv:2208.07134). Here we demonstrate that this anomalous phenomenon correlates strongly with the decrease in the degree of mutual mechanical clamping between the grains which in turn enables enhanced switching of the ferroelastic domains.