Magnetic properties of UPt 3 in the superconducting state
Magnetic properties of UPt 3 in the superconducting state
复制标题
超导态UPt 3 的磁性能
DOI：
10.1103/physrevb.57.3640
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发表时间：
1998
影响因子：
3.7
通讯作者：
H. Löhneysen
中科院分区：
文献类型：
--
作者：
A. Amann;A. Mota;M. Maple;H. Löhneysen
利用低外场下的磁性测量，对超导体UPt 3的非常规相图进行了探索。我们研究了亚稳组态的涡旋弛豫以及低场交流磁化率χ。这些数据在两个低场相A和B中的涡旋行为之间产生了明显的区别。在高温的A相，涡流被困在大部分的样品后，它在磁场中循环蠕变出预期的速率，随着温度的升高而增加。另一方面，在B相中的体涡保持如此强烈地被钉扎，以致于对于那些涡不能检测到蠕变。这种行为表明，一个内在的和非常有效的钉扎机制存在于低温超导相的UPt 3。此外，在较低的转变温度Tc −下，可以在交流磁化率的异相分量中检测到相当小的耗散峰。这两种效应可以很好地解释的概念，低温，低场B相的UPt 3的特征在于由超导序参量，打破时间反演对称性。
The unconventional phase diagram of superconducting UPt 3 has been explored using measurements of magnetic properties at low external fields. We investigated the relaxation of vortices from metastable configurations as well as the low-field ac magnetic susceptibility χ. The data yield a clear distinction between the behavior of vortices in the two low-field phases A and B. In the high-temperature A phase, vortices trapped in the bulk of the specimen after cycling it in a magnetic field creep out as expected with a rate which increases with increasing temperature. Bulk vortices in the B phase, on the other hand, remain so strongly pinned that no creep could be detected for those vortices. This behavior indicates that an intrinsic and very effective pinning mechanism exists in the low-temperature superconducting phase of UPt 3. Furthermore, a rather small dissipation peak at the lower transition temperature T c− could be detected in the out-of phase component of the magnetic ac susceptibility. Both these effects can be well explained with the notion that the low-temperature, low-field B phase of UPt 3 is characterized by a superconducting order parameter which breaks time-reversal symmetry.