Phase evolution and enhanced room temperature piezoelectric properties response of lead-free Ru doped BaTiO3 ceramic

TL;DR

This study investigates how Ru doping influences phase evolution in lead-free BaTiO3 ceramics, leading to significantly enhanced room temperature piezoelectric properties through controlled phase coexistence.

Contribution

It demonstrates that Ru doping induces phase coexistence and improves piezoelectric response in BaTiO3, providing insights for designing better lead-free piezoelectric materials.

Findings

Maximum d33 of 269 pC/N at 2 mol% Ru doping

Enhanced piezoelectric response due to phase coexistence

Ru's 4d orbital influences functional properties

Abstract

Recent years have witnessed considerable work on the development of lead-free piezoelectric ceramic materials and their structure-property correlations. The development of piezo response is a strong function of phase evolution in these materials. In this work, we report the effect of Ru doping and consequent phase evolution on maximization of piezoelectric response of polycrystalline lead-free barium titanate, depicted as Ba(RuxTi1-x)O3 (BRT). The samples were prepared in a narrow compositional range of using conventional solid-state reaction method. Ru doping increases the leakage current of BaTiO3 samples attributed to increased oxygen vacancy concentration due to substitution of Ti4+ by Ru3+. Detailed structural analysis reveals samples exhibiting coexistence of tetragonal (space group: P4mm) and orthorhombic (space group: Amm2) structured phases near the room temperature reveal relatively enhanced piezoelectric properties. The BRT sample with Ru content of 2 mol% yields a maximum longitudinal piezoelectric coefficient, d33 of 269 pC/N, a high strain value of 0.16% with a large remnant polarization of 19 micro C/cm2 and a coercive field of 5.8 kV/cm. We propose that the 4d orbital of Ruthenium plays a crucial role in improving the functional properties and in decreasing the ferroelectric Curie temperature (Tc). Our work provides clues into tailoring the phase evolution for designing lead-free piezoelectric materials with enhanced piezoelectric property.