Competing Interface and Bulk Effect-Driven Magnetoelectric Coupling in Vertically Aligned Nanocomposites
Competing Interface and Bulk Effect-Driven Magnetoelectric Coupling in Vertically Aligned Nanocomposites
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DOI：
10.1002/advs.201901000
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发表时间：
2019-08-02
期刊：
影响因子：
15.1
通讯作者：
Jia, Quanxi
中科院分区：
文献类型：
--
作者：
Chen, Aiping;Dai, Yaomin;Jia, Quanxi
室温磁电耦合是由磁致伸缩材料和电致伸缩材料组成的人工多层膜和纳米复合材料中发展起来的。虽然多层膜中的耦合机制和强度被广泛研究，但在垂直排列纳米复合材料（VAN）中它们在很大程度上未被探索，即使理论预测VAN表现出比多层结构大得多的ME耦合系数。在这里，强烈的横向和纵向ME耦合在外延BaTiO 3：CoFe 2 O 4钒测量光学二次谐波产生和压电力显微镜磁场下的耦合报告。相场模拟表明，ME耦合强度强烈依赖于垂直的界面面积，这是最终由支柱的大小控制。垂直界面耦合效应和体积守恒效应的竞争决定了VAN中的ME耦合。所揭示的机制揭示了VAN中垂直界面耦合的物理见解，其可以应用于各种具有不同功能的纳米复合材料，超出了所研究的ME耦合效应。
Room-temperature magnetoelectric (ME) coupling is developed in artificial multilayers and nanocomposites composed of magnetostrictive and electrostrictive materials. While the coupling mechanisms and strengths in multilayers are widely studied, they are largely unexplored in vertically aligned nanocomposites (VANs), even though theory has predicted that VANs exhibit much larger ME coupling coefficients than multilayer structures. Here, strong transverse and longitudinal ME coupling in epitaxial BaTiO3:CoFe2O4 VANs measured by both optical second harmonic generation and piezoresponse force microscopy under magnetic fields is reported. Phase field simulations have shown that the ME coupling strength strongly depends on the vertical interfacial area which is ultimately controlled by pillar size. The ME coupling in VANs is determined by the competition between the vertical interface coupling effect and the bulk volume conservation effect. The revealed mechanisms shed light on the physical insights of vertical interface coupling in VANs in general, which can be applied to a variety of nanocomposites with different functionalities beyond the studied ME coupling effect.