Spin-spin Relaxation Time Measurements of 2D H^^3e on Graphite
Spin-spin Relaxation Time Measurements of 2D H^^3e on Graphite
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石墨上 2D H^^3e 的自旋-自旋弛豫时间测量
DOI：
10.1088/1742-6596/400/1/012066
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
and H. Fukuyama
中科院分区：
文献类型：
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作者：
D. Sato;K. Naruse;T. Matsui;and H. Fukuyama
第二层 3 He 吸附在 Grafoil（片状石墨，预镀单层 4 He）上的自旋-自旋弛豫时间 (T 2) 和磁化率 (χ) 通过脉冲核磁共振研究，密度范围为 0.68≤ ρ≤ 5.28 nm− 2。 χ (T) 和 χ (T= 0) 的温度依赖性显示费米流体行为，即使在最低密度 ρ= 0.68 nm− 2。f= 5.5 MHz 时 T 2 的密度依赖性显示出在 ρ= 3 nm− 2 附近 5.7 ms 的宽最大值。由于在理想的 2D 流体中不能预期稀侧 T 2 的减少，因此可以将其理解为由少量固体 3 He 在基质不均匀性处引起的弛豫。我们还测量了 T 2 在 ρ= 5.28 nm− 2 时的拉莫尔频率依赖性。1/T 2 具有 f 线性依赖性，类似于早期对第一层固体 3 He 的研究 [14]。从我们的结果与之前的结果的比较来看，这种线性几乎与粒子运动无关。现在，这可能是由石墨基板的马赛克角扩展和抗磁性引起的微观磁场不均匀性引起的。
Spin-spin relaxation time (T 2) and magnetic susceptibility (χ) of the second layer 3 He adsorbed on Grafoil, exfoliated graphite, preplated with a monolayer 4 He are studied by pulsed-NMR in a density range of 0.68≤ ρ≤ 5.28 nm− 2. The temperature dependence of χ (T) and χ (T= 0) show Fermi fluid behaviour and no evidence of self-condensation are found even at the lowest density ρ= 0.68 nm− 2. Density dependence of T 2 at f= 5.5 MHz shows a broad maximum of 5.7 ms around ρ= 3 nm− 2. Since the decrease of T 2 in dilute side can not be expected in the ideal 2D fluid, it can be understood as the relaxation caused by a small amount of solid 3 He at heterogeneity of the substrate. We also measured the Larmor frequency dependence of T 2 at ρ= 5.28 nm− 2. 1/T 2 has a f-linear dependence similarly to the earlier study on a first layer solid 3 He [14]. From a comparison between our result and the earlier one, this linearity is almost independent of the particle motion. Now, it could be caused by a microscopic magnetic field inhomogeneity arisen from the mosaic angle spread and diamagnetism of the graphite substrate.