Angular dependence of the upper critical field in CaAlSi single crystal: Deviation from the Ginzburg-Landau anisotropic mass model
Angular dependence of the upper critical field in CaAlSi single crystal: Deviation from the Ginzburg-Landau anisotropic mass model
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DOI：
10.1103/physrevb.68.054507
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发表时间：
2003-08-01
影响因子：
3.7
通讯作者：
Tamegai, T
中科院分区：
文献类型：
--
作者：
Ghosh, AK;Tokunaga, M;Tamegai, T
通过磁、输运和比热测量研究了具有 AlB2 结构的 CaAlSi 中的各向异性上临界场。 H-c2 随 theta 的变化（ab 平面与应用场之间的角度）是根据不同温度下的输运测量确定的，在 theta=0 度附近显示出尖点行为，这与 Ginzburg-Landau 各向异性质量模型的预测不同。相反，角度依赖性与薄膜超导体的 Tinkham 公式一致。我们发现各向异性参数随着温度的增加而增加。 H-c2 可忽略不计的面内各向异性与该化合物中较小的平均自由程一致。
The anisotropic upper critical field in CaAlSi with an AlB2 structure has been investigated by magnetic, transport, and specific heat measurements. The variation of H-c2 with theta, the angle between the ab plane and the applied field, determined from the transport measurements at various temperatures, show a cusplike behavior near theta=0degrees unlike the prediction of the Ginzburg-Landau anisotropic mass model. Rather, the angular dependence is consistent with Tinkham's formula for thin film superconductors. We have found an increase in the anisotropy parameter with temperature. The negligible in-plane anisotropy of H-c2 is consistent with the small mean free path in this compound.