Pseudoisotropic Upper Critical Field in Cobalt-Doped SrFe2As2 Epitaxial Films
Pseudoisotropic Upper Critical Field in Cobalt-Doped SrFe2As2 Epitaxial Films
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DOI：
10.1103/physrevlett.102.117004
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发表时间：
2009-03-20
影响因子：
8.6
通讯作者：
Hosono, H.
中科院分区：
文献类型：
--
作者：
Baily, S. A.;Kohama, Y.;Hosono, H.
我们给出了钴掺杂SrFe2As2外延薄膜在0.5 K和50 T下的完整超导上临界场（H-c2）相图的电阻率测量值，作为角度（θ）和温度(T)的函数。尽管10 K时的H-c2（θ）与单波段各向异性模型的结果难以区分，但在低T时，表观各向异性H-c2（垂直于c）/H-c2（平行于c）线性减小到1。H-c2(0)=47 t时，数据可以很好地用具有小的、相反各向异性的双波段模型来描述。这种不寻常的关系被在低温度下观测到的H-c2（平行于c）的局部最大值所证实。
We present resistivity measurements of the complete superconducting upper critical field (H-c2) phase diagram as a function of angle (theta) and temperature (T) for cobalt-doped SrFe2As2 epitaxial films to 0.5 K and 50 T. Although H-c2(theta) at 10 K is indistinguishable from that derived from a single-band anisotropy model, the apparent anisotropy H-c2(perpendicular to c)/H-c2(parallel to c) linearly decreases to 1 at low T, with H-c2(0)=47 T. The data are well described by a two-band model with small, opposing anisotropies for the bands. This unusual relationship is confirmed by the observation of a local maximum for H-c2(parallel to c) at low T.