A thermodynamic potential for barium zirconate titanate solid solutions

Abstract

Barium zirconate titanate [Ba(Zr x Ti 1−x)O 3 ] 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(Zr x Ti 1−x)O 3 because there is no thermodynamic potential. In this paper, a thermodynamic potential for Ba(Zr x Ti 1−x)O 3 (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(Zr x Ti 1−x) O 3 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(Zr x Ti 1−x)O 3 solid solutions.

Theoretical Studies on Controlling the Chirality of Helical Polarization Vortices in Ferroelectric Nanowires: Implications for Reconfigurable Electronic Devices

“…On the other hand, the interface between BT and BZT05 may be a kind of mixture, where the percentage of Zr content is somewhere between 0 and 0.05, depending on the fabrication technique. According to the phase diagram of BZT materials, the ferroelectric phases appeared in the nanowire are still composed of T - and O -phases. Since the HPV structure is formed in the considered nanowire arising from the interplay between the T - and O -phases, it is expected that the HPV will also appear in the nanowire with a mixture interface.…”

“…We consider nanowires made of T-phase BT and Ophase BZT05 ferroelectrics. 26 The BT/BZT05 nanowire geometry is shown in Figure 1. The thickness ratio of BT and BZT05 layers is 1:1.…”

Monoclinic symmetry at the nanoscale in lead-free ferroelectric BaZr$_{x}$Ti$_{1-x}$O$_{3}$ ceramics

“…The BZT (BaZr x Ti 1−x O 3 ) solid solution has been proven to be a model system in search of Pb-free superior piezoceramics and has been investigated intensively due to its potentially rich phase diagram by both theoreticians as well as experimentalists [1][2][3][4][5]. The parent compound BaTiO 3 (x = 0) is a typical ferroelectric [6].…”

Electrocaloric Effect in Different Oriented BaZr0.15Ti0.85O3 Single Crystals

“…In recent years, lead-free barium zirconate titanate (BaZr x Ti 1–x O 3 ) has attracted much attention due to its rich phase structure and excellent electrocaloric (EC) properties [ 19 , 20 , 21 , 22 , 23 , 24 ]. Direct measurement by Qian et al indicates that when the change of the electric field is 2.1 MV/m, BaZr 0.2 Ti 0.8 O 3 ceramics at 38 °C exhibit an EC temperature change of 1.1 °C with a large EC coefficient of around 0.5 × 10 −6 KmV −1 [ 19 ].…”