Epitaxial BiFeO3 multiferroic thin film heterostructures
Epitaxial BiFeO3 multiferroic thin film heterostructures
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DOI：
10.1126/science.1080615
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发表时间：
2003-03-14
期刊：
影响因子：
56.9
通讯作者：
Ramesh, R
中科院分区：
文献类型：
--
作者：
Wang, J;Neaton, JB;Ramesh, R
据报道，铁电磁体 BiFeO3 的异质外延约束薄膜的极化和相关特性得到了增强。结构分析表明，薄膜的晶体结构是单斜晶系，而块体是菱面体结构。这些薄膜表现出室温自发极化（每平方厘米 50 至 60 微库仑），几乎比本体的自发极化（每平方厘米 6.1 微库仑）高一个数量级。观察到的增强得到了第一性原理计算的证实，并发现源于偏振对晶格参数微小变化的高敏感性。与本体相比，这些薄膜还表现出增强的厚度依赖性磁性。这些薄膜形式的增强和组合功能响应为创建和实现主动耦合磁和铁电有序参数的薄膜器件提供了机会。
Enhancement of polarization and related properties in heteroepitaxially constrained thin films of the ferroelectromagnet, BiFeO3, is reported. Structure analysis indicates that the crystal structure of film is monoclinic in contrast to bulk, which is rhombohedral. The films display a room-temperature spontaneous polarization (50 to 60 microcoulombs per square centimeter) almost an order of magnitude higher than that of the bulk (6.1 microcoulombs per square centimeter). The observed enhancement is corroborated by first-principles calculations and found to originate from a high sensitivity of the polarization to small changes in lattice parameters. The films also exhibit enhanced thickness-dependent magnetism compared with the bulk. These enhanced and combined functional responses in thin film form present an opportunity to create and implement thin film devices that actively couple the magnetic and ferroelectric order parameters.