EPSRC-SFI: Emergent Magnetism and Spin Interactions in Metallo-Molecular Interfaces

两种材料之间的接口可用于产生任何组件都不可能单独具有的新属性（涌现），用于调整其中一个组件中的功能（增强），或用于共享功能（接近）。我们的磁性材料种类有限；只有铁、镍和钴金属在室温下表现自发磁有序。在这里，我们使用分子界面来产生超出斯通纳准则的新型磁体，以控制薄膜的自旋特性并添加功能。从基本的角度来看，由于界面的复杂性，所涉及的材料及其复杂的量子电子特性，这些效应的起源并没有得到充分的解释。该提案的科学计划是：1 .建立一个新的理论框架来研究磁分子耦合和界面，这说明了在金属与分子之间耦合中起作用的许多物理因素。这些因素可能包括界面结构和弛豫、再杂化程度以及随后的电荷转移，这些因素导致了界面磁有序的出现和描述。通过纳米碳包覆层提高常用磁性薄膜的性能。磁性材料在计算、传感器、功率转换和产生、信号传输和许多其他技术中起着至关重要的作用。通过在三维铁磁体和/或其他金属（例如FeNi， FeCoB）之间合金化，通过与稀土（例如SmCo和NdFeB）结合，使用高自旋轨道耦合界面（例如Co/Pt）或使用氧化物来实现所需性能的调整（例如YIG）。这些策略可以导致广泛的磁各向异性，矫顽力和电导率。然而，一些功能，如磁性的电气控制，半导体和磁性的结合或提高磁性元件的阻塞温度仍然是难以捉摸的。此外，磁学和自旋电子学中使用的一些材料价格昂贵，对环境有害，而且/或者难以回收。另一方面，分子界面利用丰富的环保材料来带来新的或增强的自旋功能。这些机会包括在直径/顺磁性金属中产生自旋有序，控制矫顽力（软化/硬化），提高纳米结构的有序温度，操纵磁化轴，以及通过调整自旋轨道耦合提高自旋扭矩器件的性能。3。通过使用电场打开/关闭界面自旋排序来创造可切换磁性的机会。在磁存储器等应用中需要完全稳定的自旋顺序。然而，拥有开启和关闭样品磁响应的能力将为研究和应用开辟新的途径，从未来的高频超导电子学和量子比特，到亚波长光存储器的设计。金属分子界面的性质高度依赖于电荷转移和再杂化。因此，电或光照射可以用来控制它们的磁响应。自旋有序和极化电子转移的结果并不局限于磁性材料及其使用。电荷转移是一个重要的化学和生化过程，与自旋相关的金属-分子耦合研究也可以在未来为其他科学领域做出贡献，如电化学储能、电催化以及金属在医学成像等生物医学应用中的应用。

The interface between two materials can be used to give rise to new properties that neither component could have separately (emergence), to tune the capabilities found in of one of them (enhancement), or to share functionalities (proximity). Our range of magnetic materials is limited; only the metals iron, nickel and cobalt show spontaneous magnetic ordering at room temperature. Here, we use molecular interfaces to generate novel magnets outside the Stoner criterion, to control the spin properties of thin films and add functionalities. From a fundamental point of view, the origin of these effects is not fully explained due to the complexity of the interfaces, the materials involved and their intricate quantum-electronic properties. The scientific plan of the proposal is: i. To develop a new theoretical framework to study magneto-molecular coupling and interfaces accounting for the many physical factors at play in the coupling between metals and molecules. These factors include, possibly in combination, interface structure and relaxation, the degree of re-hybridisation and the ensuing charge-transfer for the emergence and descriptors of interfacial magnetic ordering.ii. To improve the properties of commonly used magnetic thin films via nanocarbon overlayers. Magnetic materials play a critical role in computing, sensors, power conversion and generation, signal transfer and many other technologies. Tuning of the desired properties is achieved via alloying between 3d ferromagnets and/or other metals (e.g. FeNi, FeCoB), by combining with rare earths (e.g. SmCo and NdFeB), using high spin orbit coupling interfaces (e.g. Co/Pt) or using oxides to achieve insulating ferrimagnets (e.g. YIG). These strategies can lead to a wide range of magnetic anisotropies, coercivities and conductivities. However, some functionalities, such as the electric control of magnetism, the combination of semiconducting and magnetic properties or enhancing the blocking temperature in magnetic elements remain elusive. Furthermore, some of the materials used in magnetism and spintronics are expensive, harmful to the environment and/or difficult to recycle. Molecular interfaces, on the other hand, make use of abundant, eco-friendly materials to bring about new or enhanced spin functionalities. Such opportunities include the generation of spin ordering in dia/paramagnetic metals, the control of coercivity (soften/harden), increases in the ordering temperature of nanostructures, the manipulation of the magnetisation axis, and improved performance in spin torque devices by tuning the spin orbit coupling. iii. To create the opportunity for switchable magnetism by turning on/off the interfacial spin ordering using electric fields. Fully stable spin ordering is required in applications such as magnetic memories. However, having the capability to turn on and off the magnetic response of a sample would open new avenues of research and applications, from future high frequency superconducting electronics and qubits, to the design of sub-wavelength photo-memories. The properties of metallo-molecular interfaces are highly dependent on charge transfer and re-hybridisation. Electric or optical irradiation can therefore be used to control their magnetic response.The consequences of spin ordering and polarised electron transfer are not limited to magnetic materials and their usage. Charge transfer is an essential chemical and biochemical process, and research in spin-related metallo-molecular coupling can also in the future contribute to other areas of science, such as electrochemical energy storage, electro-catalysis, and the use of metals in biomedical applications such as medical imaging.