Exploring new functionalities of magnetic materials utilizing nanoplasmonics and multiferroics

利用纳米等离子体和多铁性探索磁性材料的新功能

• 批准号: RGPIN-2018-03765
• 负责人: Choi, ByoungChul
• 金额: $ 2.04万
• 依托单位: University of Victoria
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=762956
• 关键词: Exploring; new; functionalities; magnetic; materials

The purpose of this proposal is to explore new functionalities of magnetic materials utilizing nanoplasmonics and multiferroics. In particular, we are interested in developing new ways to control magnetism optically or electrically. In the first part of the research, we will investigate the interaction between light and magnetism, which is of utmost importance in terms of fundamental science and technological applications. A specific goal is the ultrafast light control of magnetism. The strength of the interaction of light with a magnetic medium, however, is very weak, and this weak interaction has been the main challenge in optically probing or controlling magnetism. In order to overcome this drawback, we will exploit magneto-plasmonics, which combines magnetic and plasmonic functionalities. In our previous studies, we observed that the incorporation of noble-metal nanoparticles in ferromagnetic films significantly enhances magneto-optical (MO) effect. We will conduct systematic studies on the influence of plasmon resonance on MO effect, and develop a better understanding of the underlying mechanism of the enhanced MO activities. We will also study the ultrafast magnetism triggered by optically excited high energy electrons. The questions to be answered are: can we enhance the optical generation of hot electrons via localized surface plasmon resonance? If so, how effectively can we manipulate the hot-electron induced ultrafast magnetic process? Another project is to generate large wavenumber spin waves using ultrafast optical excitation. It is known that the spin wavenumber is determined by the spatial intensity distribution of the pumping light. We will be able to reduce the pump spot size to the nanoscale by using near-field optics. Higher spin wavenumbers can also be generated by using the localized surface plasmon resonance, in which the spatial intensity distribution is determined by the geometries of the nanoparticles. The second part of the research is to explore the opportunity of electric-field control of magnetism utilizing magnetoelectric multiferroics, which enables the coupling between magnetic and ferroelectric orders. However, room temperature multiferroics are very rare, with BiFeO3 (BFO) being an exception. Its drawback is that it has a very weak magnetic moment. Recently, it was found that a double perovskite material Bi2FeCrO6 (BFCO) has ferroelectricity similar to BFO with the added benefit of a strong magnetic moment. Our main goal is to answer the question whether BFCO can provide a new avenue for electric-field switching of magnetism. We will also investigate the electric-field triggered magnetization dynamics in gated BFCO thin films. Considering that the electric-field control of magnetism enabled by multiferroics has the potential to revolutionize today's electronics technology, the outcome of the proposed research will be significant.

该提案的目的是利用纳米等离子体和多铁性探索磁性材料的新功能。我们特别有兴趣开发光学或电气控制磁性的新方法。 在研究的第一部分，我们将研究光和磁之间的相互作用，这对于基础科学和技术应用至关重要。一个具体目标是磁力的超快光控制。然而，光与磁介质相互作用的强度非常弱，这种弱相互作用一直是光学探测或控制磁性的主要挑战。为了克服这个缺点，我们将利用磁等离子体技术，它结合了磁性和等离子体功能。在我们之前的研究中，我们观察到在铁磁薄膜中掺入贵金属纳米粒子可以显着增强磁光（MO）效应。我们将系统地研究等离子共振对MO效应的影响，更好地理解MO活性增强的潜在机制。我们还将研究光激发高能电子触发的超快磁性。要回答的问题是：我们能否通过局域表面等离子体共振增强热电子的光学产生？如果是这样，我们如何有效地操纵热电子感应超快磁过程？另一个项目是利用超快光激发产生大波数自旋波。已知自旋波数由泵浦光的空间强度分布决定。通过使用近场光学，我们将能够将泵浦光斑尺寸减小到纳米级。更高的自旋波数也可以通过使用局域表面等离子体共振产生，其中空间强度分布由纳米粒子的几何形状决定。 研究的第二部分是探索利用磁电多铁性材料对磁性进行电场控制的机会，从而实现磁序和铁电序之间的耦合。然而，室温多铁性材料非常罕见，BiFeO3 (BFO) 是一个例外。它的缺点是磁矩很弱。最近，人们发现双钙钛矿材料Bi2FeCrO6（BFCO）具有与BFO相似的铁电性，并具有强磁矩的优点。我们的主要目标是回答 BFCO 是否可以为磁性电场切换提供新途径的问题。我们还将研究门控 BFCO 薄膜中电场触发的磁化动力学。考虑到多铁性材料实现的磁场电场控制有可能彻底改变当今的电子技术，因此拟议研究的成果将具有重大意义。