A thermodynamic potential for barium zirconate titanate solid solutions

Jinlin Peng,Yunya Liu,Ningbo He,Kai Pan,Zhenyu Zhang,Dongliang Shan,Qiong Yang,Chihou Lei

doi:10.1038/s41524-018-0126-3

Jinlin Peng, Yunya Liu + Show 6 more

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https://doi.org/10.1038/s41524-018-0126-3

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Abstract

Barium zirconate titanate [Ba(ZrxTi1−x)O3] solid solutions are promising lead-free ferroelectric materials that have received substantial interest. Thermodynamic analysis based on phenomenological Landau–Devonshire theory is a powerful method for theoretical investigation of ferroelectric materials, but cannot be applied to Ba(ZrxTi1−x)O3 because there is no thermodynamic potential. In this paper, a thermodynamic potential for Ba(ZrxTi1−x)O3 (0 ≤ x ≤ 0.3) solid solutions is constructed, and then a thermodynamic analysis carried out. The results accurately reproduce known phase structures and their transition temperatures, with good agreement with experimentally measured polarization, dielectric, and piezoelectric constants. It is found that Ba(ZrxTi1−x)O3 solid solutions at room temperature have three phase boundaries, including a tetragonal–orthorhombic phase boundary at x = 0.013, an orthorhombic–rhombohedral phase boundary at x = 0.0798, and a rhombohedral–paraelectric phase boundary at x = 0.2135. The results also indicate that the chemical composition-induced ferroelectric–paraelectric phase boundary has superior electromechanical properties, suggesting a new way to enhance electromechanical coupling in Ba(ZrxTi1−x)O3 solid solutions.

Highlights

Ferroelectrics with switchable polarization, excellent dielectric, piezoelectric, and pyroelectric properties have a wide range of applications in memories, capacitors, actuators, sensors, and electrocaloric cooling devices.[1,2,3,4,5,6,7,8,9,10,11,12] As a typical ferroelectric material, barium titanate (BaTiO3) possesses a rich variety of phase transitions.[13]
When the BaTiO3 single crystal is cooled through Curie temperature, it undergoes a paraelectric to ferroelectric phase transition, and has a tetragonal phase structure with polarization along direction.[13]
In Ba(ZrxTi1−x)O3 system, the FE-FE phase transition temperatures TT↔O and TO↔R increase with the increase in composition of Zr, whereas the FE-PE phase transition temperature TC decreases with increasing composition x, and all three phase transitions are pinched into a single phase transition around x = 0.15,15,16 suggesting a pinched phase transition feature

Summary

ARTICLE OPEN

Jinlin Peng[1], Dongliang Shan[1], Yunya Liu[1], Kai Pan[1], Chihou Lei[2], Ningbo He1, Zhenyu Zhang[1] and Qiong Yang[1]. Barium zirconate titanate [Ba(ZrxTi1−x)O3] solid solutions are promising lead-free ferroelectric materials that have received substantial interest. Thermodynamic analysis based on phenomenological Landau–Devonshire theory is a powerful method for theoretical investigation of ferroelectric materials, but cannot be applied to Ba(ZrxTi1−x)O3 because there is no thermodynamic potential. A thermodynamic potential for Ba(ZrxTi1−x)O3 (0 ≤ x ≤ 0.3) solid solutions is constructed, and a thermodynamic analysis carried out. It is found that Ba(ZrxTi1−x) O3 solid solutions at room temperature have three phase boundaries, including a tetragonal–orthorhombic phase boundary at x = 0.013, an orthorhombic–rhombohedral phase boundary at x = 0.0798, and a rhombohedral–paraelectric phase boundary at x = 0.2135. The results indicate that the chemical composition-induced ferroelectric–paraelectric phase boundary has superior electromechanical properties, suggesting a new way to enhance electromechanical coupling in Ba(ZrxTi1−x)O3 solid solutions

INTRODUCTION

Constructing thermodynamic potential

Thermodynamic analysis

Phase structures and electromechanical properties in specific compositions

AUTHOR CONTRIBUTIONS

ADDITIONAL INFORMATION