基于功能基元界面序构的二维铁磁氧化物及其磁电耦合研究

因其丰富的物理内涵以及广泛的应用背景，低维磁性材料一直是材料和物理领域的热点。功能氧化物具备铁电、铁磁及多铁性等丰富的性能，在信息、能源等领域具有广泛的应用前景。然而，铁磁功能氧化物薄膜具有较大的临界尺寸，限制了对量子限域效应和拓扑磁结构的探索，以及低能耗、高效率信息存储器件的发展。开发具有极低临界尺寸、显著饱和磁化强度、高居里温度和可控磁各向异性的二维铁磁氧化物是磁性材料及磁电耦合领域的重要目标。本项目将探索以单晶胞厚度的功能氧化物作为功能基元，利用基元的界面序构来构筑二维铁磁功能单元，实现超越现有单相氧化物的宏观磁性能。在此基础上，我们将揭示功能基元的本征特性和序构方式对宏观二维磁性的影响，建立选择功能基元和设计序构方式的规则。最后，我们将发掘这种具有超低临界尺寸的二维铁磁单元在基于磁电耦合效应的低能耗信息存储中的应用潜力。该项目有望为发展低维磁性材料和磁电耦合效应提供全新的范例。

Low dimensional magnetic materials have attracted intense research interests in both material science and condensed matter physics research over past decades, due to a wide range of physical insights and potential applications. Functional oxides provide a rich family of materials that show versatile properties such as ferroelectricity, ferromagnetism and multiferroicity, holding promises for applications in energy and information technologies. However, thin films of ferromagnetic oxides usually show a relatively large critical thickness, which limits the search for emergent phenomena associated with dimensional confinement as well as the development of memory devices with high efficiency and low power consumption. Therefore, it is highly demanded to develop two-dimensional ferromagnetic oxides with low critical thickness, high magnetization, high Curie temperature and controllable magnetic anisotropy. Here, we propose to realize this goal by using the interfaces of functional bases, which are functional oxides with the thickness of one-unit-cell. The interfacial reconstruction can lead to novel two-dimensional material platforms that show emergent properties that are not found in single-phase oxides. Furthermore, we will reveal the underlying correlations between the interfacial reconstruction of functional bases and the two-dimensional ferromagnetism, to shed light on the design strategies. Last, we will explore the magnetoelectric coupling effects by taking advantages of the ultralow critical thickness. This research project could provide a new paradigm to develop low dimensional magnetic materials as well as the magnetoelectric devices for memory applications.