发表机构
Instituto de Física Rosario, Universidad Nacional de Rosario（罗萨里奥物理研究所，罗萨里奥国立大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过分子动力学模拟揭示，化学团簇通过空间再分布局部结构相增强BZT极化，稳定极性有序并形成拓扑涡旋，提升居里温度和矫顽场，为无铅钙钛矿设计提供定量框架。
AI 中文摘要
锆钛酸钡，Ba(Zr$_x$Ti$_{1-x}$)O$_3$（BZT），因其高度可调的铁电-弛豫体转变，是高性能电子元件的领先无铅候选材料。在本研究中，我们采用分子动力学模拟，探究局部化学团簇对铁电（x = 0.2）和弛豫（x = 0.4）两种状态下BZT结构与功能性质的影响。关键的是，我们证明Zr团簇在两种组分中均诱导了局部极化的显著增强。这种增强并非单纯的体积驱动效应，而是从根本上由局部结构相（菱方、正交和四方）的空间再分布所决定；Zr偏析形成更大、连续的富Ti区域，扩展了高极性菱方畴并促进协同偶极排列。这种协同耦合热稳定了局部极性有序，系统性地提升了居里温度、最大介电常数温度及Burns温度。聚焦于弛豫组分（x = 0.4），化学偏析促进了具有弹性的旋涡状极性拓扑结构的形成，这些结构分为围绕富Zr团簇循环的涡旋和局限于富Ti基体内的间隙涡旋。这些拓扑结构作为有效的钉扎屏障，阻碍极化反转，导致显著的电硬化及升高的矫顽场。最终，这些发现建立了纳米尺度成分异质性、极性畴拓扑与宏观性能之间的定量联系，为通过局部化学有序控制工程化无铅钙钛矿提供了稳健框架。
英文摘要
Barium zirconate titanate, Ba(Zr$_x$Ti$_{1-x}$)O$_3$ (BZT), is a leading lead-free candidate for high-performance electronic components due to its highly tunable ferroelectric-to-relaxor transition. In this study, we employ molecular dynamics simulations to investigate the effects of local chemical clustering on the structural and functional properties of BZT in both ferroelectric (x = 0.2) and relaxor (x = 0.4) regimes. Crucially, we demonstrate that Zr clustering induces a significant enhancement of local polarization across both compositions. Rather than a purely volume-driven effect, this enhancement is fundamentally governed by a spatial redistribution of local structural phases (rhombohedral, orthorhombic, and tetragonal); Zr segregation forms larger, continuous Ti-rich regions that expand highly polar rhombohedral domains and foster cooperative dipolar alignment. This cooperative coupling thermally stabilizes the local polar order, systematically elevating the Curie, maximum permittivity, and Burns temperatures. Focusing on the relaxor composition (x = 0.4), chemical segregation promotes the formation of resilient, swirling polar topological textures,categorized into vortices circulating around Zr-rich clusters and interstitial vortices localized within the Ti-rich matrix. These topological structures act as effective pinning barriers against polarization reversal, driving pronounced electrical hardening with elevated coercive fields. Ultimately, these findings establish a quantitative link between nanoscale compositional heterogeneity, polar domain topology, and macroscopic performance, providing a robust framework for engineering lead-free perovskites via local chemical order control.
CommentsAccepted for publication in Materials Today Physics
