{"title":"High temperature solution phase diagram of lead zirconate titanate","authors":"Vincent J. Fratello, Song Won Ko","doi":"10.1016/j.jcrysgro.2024.127671","DOIUrl":null,"url":null,"abstract":"<div><p>Lead zirconate titanate (PZT) of composition Pb(Zr<em><sub>X</sub></em>Ti<sub>1−</sub><em><sub>X</sub></em>)O<sub>3</sub> is a non-congruently melting material, so crystal growth must be done from a high temperature solution. An understanding of the high temperature solution phase diagram is necessary to make this possible. A variety of solvent systems and solvent properties were evaluated for the growth of PZT, and two innovative lead oxide-phosphate solvents were developed: PbO-PbLiPO<sub>4</sub> (PLP), and PbO-Pb<sub>2</sub>P<sub>2</sub>O<sub>7</sub> (lead pyrophosphate). PZT crystals were grown from these solvents with compositions near the desirable morphotropic phase boundary composition <em>X</em> = 0.52. Both PLP and Pb<sub>2</sub>P<sub>2</sub>O<sub>7</sub> form molecular complexes in the melt that participate minimally in the solution of PZT, which is dissolved by the free uncomplexed PbO acting as both a solvent and solute ingredient. The phosphates do favorably reduce the melting temperature, PbO evaporation, density, and position of the melting minimum. These solvents were used to determine liquidus and solidus curves over the range of interest in <em>X</em>, and to develop a universal solubility equation. Modeling was used to fit and extrapolate these PZT-solvent phase diagrams to other PbO-based solvents. These results explain prior art data and point to a congruently melting indifferent point at the lead titanate end of the phase diagram.</p></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":null,"pages":null},"PeriodicalIF":1.7000,"publicationDate":"2024-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Crystal Growth","FirstCategoryId":"88","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0022024824001064","RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"CRYSTALLOGRAPHY","Score":null,"Total":0}
引用次数: 0
Abstract
Lead zirconate titanate (PZT) of composition Pb(ZrXTi1−X)O3 is a non-congruently melting material, so crystal growth must be done from a high temperature solution. An understanding of the high temperature solution phase diagram is necessary to make this possible. A variety of solvent systems and solvent properties were evaluated for the growth of PZT, and two innovative lead oxide-phosphate solvents were developed: PbO-PbLiPO4 (PLP), and PbO-Pb2P2O7 (lead pyrophosphate). PZT crystals were grown from these solvents with compositions near the desirable morphotropic phase boundary composition X = 0.52. Both PLP and Pb2P2O7 form molecular complexes in the melt that participate minimally in the solution of PZT, which is dissolved by the free uncomplexed PbO acting as both a solvent and solute ingredient. The phosphates do favorably reduce the melting temperature, PbO evaporation, density, and position of the melting minimum. These solvents were used to determine liquidus and solidus curves over the range of interest in X, and to develop a universal solubility equation. Modeling was used to fit and extrapolate these PZT-solvent phase diagrams to other PbO-based solvents. These results explain prior art data and point to a congruently melting indifferent point at the lead titanate end of the phase diagram.
期刊介绍:
The journal offers a common reference and publication source for workers engaged in research on the experimental and theoretical aspects of crystal growth and its applications, e.g. in devices. Experimental and theoretical contributions are published in the following fields: theory of nucleation and growth, molecular kinetics and transport phenomena, crystallization in viscous media such as polymers and glasses; crystal growth of metals, minerals, semiconductors, superconductors, magnetics, inorganic, organic and biological substances in bulk or as thin films; molecular beam epitaxy, chemical vapor deposition, growth of III-V and II-VI and other semiconductors; characterization of single crystals by physical and chemical methods; apparatus, instrumentation and techniques for crystal growth, and purification methods; multilayer heterostructures and their characterisation with an emphasis on crystal growth and epitaxial aspects of electronic materials. A special feature of the journal is the periodic inclusion of proceedings of symposia and conferences on relevant aspects of crystal growth.