Magnetic and Thermodynamic Study of Solid 3He

固体 3He 的磁学和热力学研究

• 批准号: 0096791
• 负责人: E. Dwight Adams
• 金额: $ 33.03万
• 依托单位: University of Florida
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-03-15 至 2005-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0096791&HistoricalAwards=false
• 关键词: Magnetic; Thermodynamic; Study; Solid; 3He

This project will investigate magnetic and thermodynamic properties of solid 3H near the nuclear ordering transition. The nuclear magnetism of bulk 3He will be studied as a function of pressure and magnetic field. The magnetic properties of a new form of 3He will also be studied. The new form consists of nanoclusters of 3He that have been precipitated in a matrix of 4He. Surface effects may be significant since an appreciable fraction of he 3He is within a few layers of the surface. Ferromagnetism in the high-pressure hcp phase will be investigated by measuring the frequency spectrum and the magnetization. A companion study at the Hahn-Meitner Institute Berlin will use neutron scattering to characterize the hcp phase, as well as the high magnetic field phase of the low pressure, bcc phase. The critical field for the transition from the high-field phase to the disordered paramagnetic phase will be investigated through the field-dependence of the melting pressure. Graduate students, undergraduates and postdoctoral associates involved in the project will receive training in cutting edge techniques, which prepare them for a range of careers in academe, industry, and government.This project will study the magnetic properties of the helium isotope, 3He, at ultra-low temperatures, where the nuclei of the atoms interact and order themselves in fashion analogous to the way iron atoms couple to form a ferromagnet (though at much higher temperature). The study of 3He at ultralow temperatures can shed light on fundamental magnetism that may have implications for high temperature materials such as iron. There are several different magnetic and structural phases of 3He that occur as a function of pressure and magnetic field. Nuclear magnetic resonance (NMR) and other magnetic techniques will be employed. Another study will look at the magnetic properties of small nanoclusters of 3He that can be formed in a matrix of 4He. These nanoclusters have interesting magnetic properties that depend on their small size and on the interaction of their surface atoms with the surrounding 4He atoms. Collaboration with the Hahn-Meitner Institute in Berlin will combine neutron scattering with low temperature physics techniques to prepare and study the low- and high-pressure nuclear magnetic phases of 3He. Graduate students, undergraduates and postdoctoral associated involved in the project will receive training in cutting edge techniques, which prepare them for a range of careers in academe, industry, and government.

本计画将探讨固态3 H在核序转变附近的磁性与热力学性质。 研究了~ 3 He的核磁特性随压力和磁场的变化。 还将研究一种新形式的3 He的磁性。 新的形式由3 He的纳米团簇组成，这些纳米团簇已经沉淀在4 He的基质中。 表面效应可能是显着的，因为相当大的一部分氦3 He是在表面的几层。 通过测量频谱和磁化强度，研究高压hcp相的铁磁性。 柏林哈恩-迈特纳研究所的一项配套研究将使用中子散射来表征hcp相，以及低压bcc相的高磁场相。 从高场相到无序顺磁相的过渡的临界场将通过熔化压力的场依赖性来研究。 参与该项目的研究生、本科生和博士后将接受尖端技术培训，为他们在工业、工业和政府部门的一系列职业生涯做好准备。该项目将研究氦同位素3 He在超低温下的磁性，其中原子核以类似于铁原子耦合形成铁磁体的方式（尽管在高得多的温度下）相互作用并自行排序。在超低温下对3 He的研究可以揭示可能对铁等高温材料产生影响的基本磁性。 有几个不同的磁性和结构相的3 He发生的压力和磁场的函数。 将采用核磁共振（NMR）和其他磁性技术。 另一项研究将研究可以在4 He基质中形成的3 He小纳米团簇的磁性。 这些纳米团簇具有有趣的磁性，这取决于它们的小尺寸和它们的表面原子与周围的4 He原子的相互作用。 与柏林的哈恩-迈特纳研究所合作，将联合收割机中子散射与低温物理技术相结合，制备和研究氦-3的低压和高压核磁相。参与该项目的研究生、本科生和博士后将接受尖端技术培训，为他们在工业、工业和政府领域的职业生涯做好准备。