Magnetic and Thermodynamic Study of Solid 3He

本项目将研究固体~3H在核有序转变附近的磁学和热力学性质。3He块体的核磁性将作为压力和磁场的函数进行研究。还将研究一种新形式的3He的磁性。新的形式由3He纳米团簇组成，这些纳米团簇已经在4He基质中沉淀。表面效应可能是显著的，因为相当一部分He~3He在表面的几层之内。通过测量频谱和磁化强度来研究高压hcp相中的铁磁性。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。通过熔化压力的场依赖关系，研究了高场相向无序顺磁相转变的临界场。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，为他们在学术界、工业界和政府的一系列职业生涯做好准备。该项目将研究氦同位素3He在超低温下的磁性，在超低温下，原子核之间的相互作用和排列方式类似于铁原子相互作用形成铁磁体的方式(尽管在更高的温度下)。对超低温下~3He的研究可以揭示基本磁性，这可能会对铁等高温材料产生影响。作为压力和磁场的函数，3He有几个不同的磁相和结构相。将使用核磁共振(核磁共振)和其他磁性技术。另一项研究将着眼于可以在4He基质中形成的3He纳米小团簇的磁性。这些纳米团簇具有有趣的磁性，这取决于它们的小尺寸以及它们的表面原子与周围的4He原子的相互作用。与柏林的哈恩-迈特纳研究所合作，将把中子散射和低温物理技术结合起来，准备和研究3He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方面的培训，为他们在学术界、工业界和政府的一系列职业生涯做好准备。

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.