RESEARCH ON HELIUM 3 IN MICROSCOPIC GEOMETRY

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具有根本的重要性。本文测量了<@ D_（13）@> D_1He在受限几何中的比热。该样品是通过将<@D13@> D1 He离子射入Ag箔中并对箔进行退火而产生的，这导致直径约100 A的<@D13@> D1 He气泡。<@D13@> D1 He在金属箔冷却到低温时液化。我们已经测量了箔在13 mK（] SY. ltorsim）的热弛豫时间。[）T（] SY.ltorsim. 1.2K，并测定了<@D13@> D1 He气泡的比热，它不同于<@D13@> D1 He的比热。我们的数据表明，<@D13@> D1 He在Ag衬底上的第二层显示出恒定的比热。这意味着这种二维液体的费米温度必须是T<@D2F@>D2 < 40 mK，表明靠近Ag衬底的<@D13@> D1 He的磁相互作用非常强的增强。另一种受限几何形状的<@D13@> D1 He液体样品如下制备：将含有0.9atm%<@D13@> D1 He的<@D14@> D1 He加压至32巴并冷却，这导致hcp <@D14@> D1 He中的<@D13@> D1 He液滴低于约70 mK。比热数据表明，只有部分分离的<@D13@> D1 He被液化，液态<@D13@> D1 He的行为与体相<@D13 @> D1 He的行为相似，而<@D13@> D1 He在Ag衬底中的行为不同。我们正在对在毫开尔文温度下烧结非常细的（100埃）Pt粉末而产生的受限几何形状的液态^3He进行比热测量。

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.