Anisotropic vortex pinning in the layered intermetallic superconductor CaAlSi
Anisotropic vortex pinning in the layered intermetallic superconductor CaAlSi
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DOI：
10.1103/physrevb.68.134503
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发表时间：
2003-10
影响因子：
3.7
通讯作者：
A. Ghosh;Y. Hiraoka;M. Tokunaga;T. Tamegai
中科院分区：
文献类型：
--
作者：
A. Ghosh;Y. Hiraoka;M. Tokunaga;T. Tamegai
我们研究了具有中等各向异性的层状金属间超导体CaAlSi的各向异性磁性能。在上临界场附近，$H||c$ 在低温下存在显着的峰值效应，而 $H||\mathrm{ab}$ 则变得较弱。$ 估计的相关长度 ${L}_{c}$ 表明在峰值效应周围存在三维集体钉扎。已提取并比较了 $H||c$ 和 $H||\mathrm{ab}$ 的临界电流密度。 CaAlSi 中的磁通钉扎机制是各向异性的。 $H||c$ 观察到集体核心钉扎，而 $H||\mathrm{ab}$ 则存在偏离的特征。$ 涡旋相图，包括上临界场、不可逆场和峰值场，都已被研究。热力学临界场和Ginzburg-Landau 参数是根据平衡磁化强度估计的。讨论了最大钉扎力密度与热力学临界场的缩放性质。伦敦穿透深度的温度依赖性与 CaAlSi 中的单全带隙态一致。
We have studied anisotropic magnetic properties of layered intermetallic superconductor CaAlSi with moderate anisotropy. Near the upper critical field there is a prominent peak effect for $H||c$ at low temperatures and it becomes weaker for $H||\mathrm{ab}.$ The estimated correlation length ${L}_{c}$ suggests the presence of three-dimensional collective pinning around the peak effect. The critical current densities for $H||c$ and $H||\mathrm{ab}$ have been extracted and compared. Flux pinning mechanism in CaAlSi is anisotropic. Collective core pinning is observed for $H||c$ whereas there is a signature of deviation from it for $H||\mathrm{ab}.$ The vortex phase diagram, including the upper critical field, irreversibility field, and peak field, has been studied. The thermodynamic critical field and Ginzburg-Landau parameter have been estimated from the equilibrium magnetization. The nature of scaling of the maximum pinning force densities with the thermodynamic critical field has been discussed. The temperature dependence of London penetration depth is consistent with single fully gapped state in CaAlSi.