Nuclear Magnetic Ordering in Metals and Superfluid Four-Helium in Porous Media

多孔介质中金属和超流四氦的核磁有序化

• 批准号: 8902538
• 负责人: Yasumasa Takano
• 金额: --
• 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: 1990
• 资助国家: 美国
• 起止时间: 1990-01-15 至 1993-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8902538&HistoricalAwards=false
• 关键词: Nuclear; Magnetic; Ordering; Metals; Superfluid

Research into two main areas is proposed. (1) Nuclear magnetic order will be investigated below 100 nK in Ag, Au and Rh. AC magnetic susceptibility and low-frequency cw-NMR measurements will be used to characterize the phase diagram. (2) A torsional pendulum technique will be used to study the superfluid density and the energy dissipation of helium-four confined in various geometries, including Zeolite, silica gel and Vycor glasses. Effects of pore size, substrate randomness and flow on the superfluid transition will be examined.

提出了两个主要方面的研究。(1)对Ag、Au和Rh在100nK以下的核磁有序进行了研究。将使用交流磁化率和低频CW-核磁共振测量来表征相图。(2)用扭摆技术研究了沸石、硅胶和Vycor玻璃等不同几何形状氦-4的超流密度和能量耗散。将考察孔径大小、基质随机性和流量对超流体转变的影响。