Exotic Magnetism in Geometrically Frustrated Magnets Under Extreme Conditions

上个世纪的许多技术进步，从集成电路到磁共振成像中使用的磁铁，都是由于对固体中电子、磁性和晶格自由度之间相互作用的理解。尽管取得了惊人的进步，但未来的创新仍然面临挑战，这些挑战受到对多体效应和量子力学的理解的限制。未来的许多发展很可能在所谓的量子材料中找到，当暴露在极端条件下，如高磁场、低温或高压下，它们会显示出物质的奇异状态。高温超导体是这类材料的突出例子。将压力应用于量子材料，作为对这些物质新状态的探测，是理解这些化合物的成功途径。例如，化学压力，通过化学取代较大或较小的阳离子进入已建立的固态结构，已经成功地阐明了固体中复杂的电子和磁性现象。这导致了对物质的全新电子状态的探索。通过高压方法合成新材料一直是一个快速发展的研究领域，并有助于广泛扩大已知几何挫折磁铁的数量。以极端条件下的几何挫折为中心主题，PI将采取以下多方面的方法来研究量子材料：(1)扩展高压合成技术：温尼伯大学与爱丁堡大学极端条件科学中心（CSEC）合作，在高压下合成新材料。(2)新材料的热力学性质表征：新合成材料将继续使用温尼伯大学的x射线衍射和低温能力，以及国家高磁场实验室（Tallahassee, Florida）和爱丁堡大学（CSEC）的设备进行研究。(3)利用中子散射、x射线散射和μ子自旋弛豫进行新材料的结构和磁性研究：PI目前利用中子散射、x射线散射和μ子自旋弛豫等探针进行的研究计划将扩展到包括高压探针。(4)晶体生长技术的扩展：将利用橡树岭国家实验室的高压成像炉探索高压晶体生长技术。这四个领域的发展将由一个教育项目来补充，该项目不仅涉及温尼伯大学的本科生，还包括通过马尼托巴大学和麦克马斯特大学的私人学院联合任命的研究生。

Many of the technological advances of the last century, from the integrated circuit to the magnets used in magnetic resonance imaging, have been due to an understanding of the interplay between the electronic, magnetic, and lattice degrees of freedom in solids. Despite this staggering level of progress, challenges remain towards future innovations which are limited by an understanding of many-body effects and quantum mechanics. Many of the developments of the future are likely to be found in so-called quantum materials, which show exotic states of matter when exposed to extreme conditions such as high magnetic fields, low temperatures, or high applied pressures.  High temperature superconductors are prominent examples of this class of materials. The application of pressure to quantum materials as a probe of these new states of matter has been a successful route towards understanding these compounds.  Chemical pressure, for example, through the chemical substitution of larger or smaller cations into established solid state structures, has been a successful route to elucidating complicated electronic and magnetic phenomena in solids.  This has led to the exploration of entirely new electronic states of matter.  The synthesis of new materials via high pressure methods has been a rapidly growing area of research, and has helped to widely expand the number of known geometrically frustrated magnets.  Using geometrical frustration under extreme conditions as a central theme, the PI will take the following multifaceted approach to the study of quantum materials: (1) Expansion of high pressure synthesis techniques: A collaboration has been made between the University of Winnipeg and the Centre for Science at Extreme Conditions (CSEC) at the University of Edinburgh to synthesize new materials under high pressure. (2) Characterization of the thermodynamic properties of new materials: Newly synthesized materials will continue to be studied using the x-ray diffraction and low temperature capabilities at the University of Winnipeg, and also using the equipment at the National High Magnetic Field Laboratory (Tallahassee, Florida), and the University of Edinburgh (CSEC). (3) Structural and magnetic studies of new materials using neutron scattering, x-ray scattering and muon spin relaxation: The current research program of the PI using probes such as neutron scattering, x-ray scattering, and muon spin relaxation will be expanded to incorporate high pressure probes. (4) Expansion of crystal growth techniques: High pressure crystal growth techniques will be explored using the high pressure image furnaces at the Oak Ridge National Laboratory.  These four areas of growth will be complemented by an educational program that involves not only undergraduate students at the University of Winnipeg, but also graduate students through the PIs joint appointment at the University of Manitoba and McMaster University.