RESEARCH ON HELIUM 3 IN MICROSCOPIC GEOMETRY

氦 3 的微观几何研究

基本信息

批准号：
03640343
负责人：
FUJII Yoshiko
金额：
$ 1.22万
依托单位：
OKAYAMA UNIVERSITY OF SCIENCE
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1991
资助国家：
日本
起止时间：
1991 至 1992
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-03640343/
关键词：
Liquid helium 3 Size effect Wall effect Fermi temperature Paramagnon 比熱核断熱消磁残留抵抗比焼結体

项目摘要

The influence of dimensionality and of finite size on magnetism, specific heat, superfluidity, statics or other properties is of fundamental importance in physics. We have measured the specific heat of liquid <@D13@>D1He in a restricted geometry. The sample is produced by shooting <@D13@>D1He ions into Ag foils and annealing the foils, which results in <@D13@>D1He gas bubbles of diameter about 100 A. The <@D13@>D1He liquifies when the metal foils are cooled to low temperatures. We have measured the thermal relaxation time of the foils at 13 mK (] SY.ltorsim.[) T (] SY.ltorsim.[) 1.2 K, and have determined the specific heat of the <@D13@>D1He bubbles ; it differs from the specific heat of bulk liquid <@D13@>D1He. Our data indicate that the second layer of <@D13@>D1He on a Ag substrate shows a constant specific heat. This mean that the Fermi temperature of this two-dimensional liquid has to be T<@D2F@>D2 < 40 mK, pointing to a very strong enhancement of the magnetic interactions of the <@D13@>D1He close to the Ag substrate. Another sample of liquid <@D13@>D1He in a restricted geometry is produced as follows ; the <@D14@>D1He containing 0.9 atm % <@D13@>D1He is pressurized up to 32 bar and cooled, which results in <@D13@>D1He droplets in the hcp <@D14@>D1He below about 70 mK. The specific heat data show that only a part of the separated <@D13@>D1He is liquified and the behavior of the liquid <@D13@>D1He is similar to the bulk liquid <@D13@>D1He in contrast with the <@D13@>D1He droplets in Ag substrate.In order to clarify the behavior of the second layer of ^3He on substrate, we are carrying on a specific heat measurements of liquid ^3He in a restricted geometry produced by sintering the very fine (100 A) Pt powders at millikelvin temperatures.

维度和有限尺寸对磁性、比热、超流性、静力学或其他性质的影响在物理学中至关重要。我们在有限的几何形状下测量了液体 <@D13@>D1He 的比热。该样品是通过将 <@D13@>D1He 离子射入银箔并对箔进行退火而产生的，从而产生直径约为 100 A 的 <@D13@>D1He 气泡。当金属箔熔化时，<@D13@>D1He 会液化。被冷却至低温。我们测量了箔在 13 mK (] SY.ltorsim.[) T (] SY.ltorsim.[) 1.2 K 下的热弛豫时间，并确定了 <@D13@>D1He 气泡的比热；它不同于散装液体<@D13@>D1He 的比热。我们的数据表明，Ag 基底上的第二层 <@D13@>D1He 显示出恒定的比热。这意味着这种二维液体的费米温度必须为 T<@D2F@>D2 < 40 mK，这表明靠近 Ag 基底的 <@D13@>D1He 的磁相互作用有非常强的增强。受限几何形状的另一个液体<@D13@>D1He 样品的制备如下；将含有 0.9 atm % <@D13@>D1He 的 <@D14@>D1He 加压至 32 bar 并冷却，这会导致 hcp <@D14@>D1He 中的 <@D13@>D1He 液滴低于约 70 mK。比热数据表明，只有一部分分离的<@D13@>D1He 被液化，并且液体<@D13@>D1He 的行为与本体液体<@D13@>D1He 相似，而<@D13@>D1He 与<@D13@>D1He 相比， D13@>D1He 液滴在 Ag 基底上。为了阐明基底上第二层 ^3He 的行为，我们对液体 ^3He 在受限几何形状中进行比热测量在毫开温度下烧结非常细的 (100 A) Pt 粉末。