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: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=714954
• 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未来五年研究计划的重点：(1)发现新的基于技术的金属间化合物(2)探索基于铕的金属间化合物中的奇异磁有序(3)研究价不稳定性和含钇体系中的磁有序。