Modification of the 3He Phase Diagram by Anisotropic Disorder
Modification of the 3He Phase Diagram by Anisotropic Disorder
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DOI：
10.1103/physrevlett.107.235504
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发表时间：
2011-11-30
影响因子：
8.6
通讯作者：
Parpia, J. M.
中科院分区：
文献类型：
--
作者：
Bennett, R. G.;Zhelev, N.;Parpia, J. M.
最近预测单轴压缩气凝胶可以稳定各向异性 A 相而不是各向同性 B 相，受此启发，我们测量了 10% 轴向压缩、98% 多孔气凝胶中夹带的 He-3 的压力依赖性超流体分数。我们观察到温度-压力相图的大部分区域被亚稳态 A 相占据。在 T-c 超流性消失之前，从 B 相升温后 A 相的重新出现与其在未压缩气凝胶中的缺失形成鲜明对比。相图是在纯 He-3 的基础上进行修改的，即使在零外加磁场下，多临界点 (PCP) 也消失了，并且出现了延伸到 He-3 的 PCP 下方的 A 相区域。未观察到通过压缩实现的 A 相纹理的预期排列。
Motivated by the recent prediction that uniaxially compressed aerogel can stabilize the anisotropic A phase over the isotropic B phase, we measure the pressure dependent superfluid fraction of He-3 entrained in 10% axially compressed, 98% porous aerogel. We observe that a broad region of the temperature-pressure phase diagram is occupied by the metastable A phase. The reappearance of the A phase on warming from the B phase, before superfluidity is extinguished at T-c, is in contrast to its absence in uncompressed aerogel. The phase diagram is modified from that of pure He-3, with the disappearance of the polycritical point (PCP) and the appearance of a region of A phase extending below the PCP of bulk He-3, even in zero applied magnetic field. The expected alignment of the A phase texture by compression is not observed.