Magnetism of Solid Helium-3

9421034亚当斯将在低至20微开尔文的温度和高达20特斯拉的磁场下研究固体氦-3的核磁性的几个问题。高压六方密闭堆积相中的有序化将通过利用氦核进行第二阶段退磁来实现，由于三重交换的主导作用，预计该相将是铁磁性的。在20特斯拉附近发生的高场到顺磁的相变将通过测量熔化压力来研究，以获得磁化强度。我们将通过核磁共振和热输运测量来研究三相点附近低场(低场、高场和顺磁相共存的地方)的这种转变的性质。这三项研究将对这种模型磁性物质的基本行为提供更多的洞察。固体氦-3被认为是研究磁学基本原理的模型磁系统。由于原子之间的小质量和弱作用力，感兴趣效应发生在绝对零度附近的温度范围内，低于电子系统的感兴趣温度，但高于重核磁铁的感兴趣温度。由于氦是高度可压缩的，所以可以通过施加中等压力来研究在很大的密度范围内的影响。特别是，可以研究在两种不同类型的晶体中出现的磁结构的类型。研究方法包括核磁共振、熔化压力、恒容压力和热导率。所获得的知识将有助于理解更复杂的磁系统中的磁现象。***

9421034 Adams Several problems in nuclear magnetism of solid helium-3 will be investigated at temperatures as low as 20 microkelvin and magnetic fields up to 20 Tesla. Ordering in the high-pressure hexagonal-closed packed phase, which is expected to be ferromagnetic because of the dominance of triple exchange, will be achieved by using the helium nuclei for the second stage demagnetization. The high field to paramagnetic phase transition, which occurs near 20 Tesla where the system becomes fully magnetized, will be studied by measurement of the melting pressure to obtain the magnetization. The nature of this transition at low fields near the triple point ( where the low-field, high-field, and paramagnetic phases coexist) will be investigated by nuclear magnetic resonance and thermal transport measurements. These three investigations will provide additional insight into the fundamental behavior of this model magnetic substance. %%% Solid helium-3 is considered a model magnetic system for studying fundamentals of magnetism. Because of the small mass and weak forces between atoms, the effect of interest occur in a range of temperature near absolute zero, below that of interest for electronic systems, but above those for heavy nuclear magnets. Since the helium is highly compressible, effects can be investigated over a wide range of density by application of moderate pressure. In particular, the type of magnetic structures occurring in two different type of crystals can be studied. Methods of investigation include nuclear magnetic resonance, melting pressure, constant-volume pressure, and thermal conductivity. Knowledge gained will be of use in understanding magnetic phenomena in more complicated magnetic systems. ***