Investigating complex, marginal and exotic magnetic ordering in rare-earth based materials

研究稀土基材料中复杂、边际和奇异的磁序

• 批准号: RGPIN-2020-04211
• 负责人: Ryan, Dominic
• 金额: $ 1.75万
• 依托单位: McGill University
• 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=762573
• 关键词: Investigating; complex; marginal; exotic; magnetic

Three primary themes will be the focus of the next five years of my research program: (1) Discovering new technetium-based intermetallic compounds (2) Exploring exotic magnetic ordering in europium-based intermetallic compounds (3) Investigating valence instabilities and magnetic ordering in ytterbium-containing systems. The first theme will involve the creation of a new facility to handle technetium and prepare single-crystal samples using it. Technetium is remarkable. It is the lightest element that lacks a stable isotope. Indeed it is the only radioactive element in the main s,p,d block of the periodic table. It sits directly below manganese and shares its half-filled d5 electronic configuration, opening the possibility of 4d magnetism. Some compounds, notably oxides and halides are known to be magnetic, and some metallic systems are superconducting, but very few of its intermetallic compounds have ever been prepared and fewer still have been investigated for magnetism. While it unlikely that any compound of technetium will see direct applications (its 6-day parent 99Mo is a key medical isotope, used in the diagnosis of heart problems and cancers) the knowledge gained will lead to a better understanding of magnetic systems. The second theme is Eu-based materials. Recent theoretical and experimental discoveries of topological semi-metals (TSM) and Weyl semi-metals are opening exciting frontiers of science at the boundaries of materials science and magnetism. The hope is that understanding the basic principles of TSM and WSM systems will deliver new materials platforms for photodetection, spintronics and quantum computing. I will be working with teams from the AmesLab in Iowa studying a wide range of Eu-based materials using Mössbauer spectroscopy and neutron diffraction. We have already identified some materials that have potential as magnetic refrigerants offering greenhouse gas (GHG) free refrigeration and have several more systems that we are studying. The third theme is Yb-based materials. Ytterbium exhibits a significant valence instability that leads to a rather fragile magnetic moment. We will combine 170Yb Mössbauer spectroscopy with neutron diffraction to investigate these systems. In addition, several Yb compounds show promise for thermoelectric power generation (direct conversion of waste heat into electricity). Many rely on the presence of "rattlers", weakly bound rare-earth or alkaline earth metals. There are few direct ways to investigate these almost-isolated atoms, however the digital time-differential perturbed angular correlation (TDPAC) spectrometer that we designed and built is perfect for the project. We will work with teams from Italy and the US on these projects.

三个主要主题将是我研究计划的接下来的五年的重点：（1）发现基于技术的基金间化合物（2）探索基于Europium的基于Europium的金属间化合物（3）研究价不稳定性和含Ytterbium键入系统中的磁性的外来磁性顺序。第一个主题将涉及创建一个新的设施来处理Technetium并使用它准备单晶样本。 Technetium非常出色。它是缺乏稳定同位素的最轻元素。实际上，它是元素周期表的主s，p，d块中唯一的放射性元件。它位于锰直接下方，并共享其半充满D5的电子构型，从而打开了4D磁性的可能性。某些化合物，尤其是氧化物和卤化物是磁性的，并且某些金属系统是超导的，但是已经准备好了其金属间化合物中的很少的金属化合物，并且对磁性的研究仍然很少。尽管任何化合物的technetium都不可能看到直接应用（其6天的父母99MO是一种关键的医学同位素，用于心脏问题和癌症的诊断），但获得的知识将导致对磁系统的更好理解。第二个主题是基于欧盟的材料。拓扑半金属（TSM）和Weyl半金属的最新理论和实验发现在材料科学和磁性的边界开放了令人兴奋的科学领域。希望是了解TSM和WSM系统的基本原理将提供新的材料平台，以进行光电检测，SpinTronics和量子计算。我将与爱荷华州Ameslab的团队合作，使用Mössbauer光谱和中子衍射研究广泛的欧盟材料。我们已经确定了一些具有潜力的材料，它们是提供温室气体（GHG）不含制冷的磁制冷剂，并且我们正在研究的更多系统。第三个主题是基于YB的材料。 Ytterbium表现出显着的价不稳定，导致相当脆弱的磁矩。我们将将170ybMössbauer光谱与中子衍射相结合，以研究这些系统。此外，几种YB化合物显示了热电发电的希望（将废热直接转换为电力）。许多人依靠“响尾蛇”的存在，弱绑定的稀土或酗酒的地球金属。几乎没有直接研究这些几乎分散的原子的方法，但是我们设计和构建的数字时间差异性角相关（TDPAC）光谱仪非常适合该项目。我们将与意大利和美国的团队合作进行这些项目。