Unusual upper critical field of the ferromagnetic superconductor UCoGe.
Unusual upper critical field of the ferromagnetic superconductor UCoGe.
复制标题
铁磁超导体 UCoGe 不寻常的上临界场。
DOI：
10.1103/physrevlett.100.077002
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发表时间：
2008
影响因子：
8.6
通讯作者：
A. Visser
中科院分区：
文献类型：
--
作者：
N. T. Huy;D. Nijs;Y. Huang;A. Visser
本文报道了铁磁超导体UCoGe单晶样品的上临界场B（c ~ 2）（T）测量结果。对于沿着正交轴施加的场，得到的B（c2）（0）超过了平行于B，B的泡利极限，并显示出强的各向异性B（c2）（a）近似为B（c2）（B）>>B（c2）（c）。这为等自旋配对态和超导能隙函数的轴对称性提供了证据，其中点节点沿着c轴，这也是单轴铁磁矩m（0）= 0.07 μ（B）的方向。在B（c ~ 2）的温度变化中观察到一个不寻常的弯曲或扭结，这可能表明UCoGe是一个双带铁磁超导体。
We report upper critical field B(c2)(T) measurements on a single-crystalline sample of the ferromagnetic superconductor UCoGe. B(c2)(0) obtained for fields applied along the orthorhombic axes exceeds the Pauli limit for B parallela,b and shows a strong anisotropy B(c2)(a) approximately B(c2)(b)>>B(c2)(c). This provides evidence for an equal-spin pairing state and a superconducting gap function of axial symmetry with point nodes along the c axis, which is also the direction of the uniaxial ferromagnetic moment m(0)=0.07micro(B). An unusual curvature or kink is observed in the temperature variation of B(c2) which possibly indicates UCoGe is a two-band ferromagnetic superconductor.