中国物理B ›› 2020, Vol. 29 ›› Issue (9): 97405-097405.doi: 10.1088/1674-1056/ab9f26

• • 上一篇    下一篇

Anisotropy of Ca0.73La0.27(Fe0.96Co0.04)As2 studied by torque magnetometry

Ya-Lei Huang(黄亚磊), Run Yang(杨润), Pei-Gang Li(李培刚), Hong Xiao(肖宏)   

  1. 1 Department of Physics, Zhejiang Sci-Tech University, Hangzhou 310018, China;
    2 Center for High Pressure Science and Technology Advanced Research, Beijing 100094, China;
    3 Laboratorium für Festkörperphysik, ETH-Zürich, 8093, Zürich, Switzerland;
    4 Department of Physics, Beijing University of Posts and Telecommunications, Beijing 100876, China
  • 收稿日期:2020-06-06 修回日期:2020-06-12 接受日期:2020-06-23 出版日期:2020-09-05 发布日期:2020-09-05
  • 通讯作者: Pei-Gang Li, Hong Xiao E-mail:pgli@bupt.edu.cn;hong.xiao@hpstar.ac.cn
  • 基金资助:
    Project supported by NSAF, China (Grant No. U1530402). P. G. Li acknowledges the support of the National Natural Science Foundation of China (Grant No. 51572241).

Anisotropy of Ca0.73La0.27(Fe0.96Co0.04)As2 studied by torque magnetometry

Ya-Lei Huang(黄亚磊)1,2, Run Yang(杨润)3, Pei-Gang Li(李培刚)1,4, Hong Xiao(肖宏)2   

  1. 1 Department of Physics, Zhejiang Sci-Tech University, Hangzhou 310018, China;
    2 Center for High Pressure Science and Technology Advanced Research, Beijing 100094, China;
    3 Laboratorium für Festkörperphysik, ETH-Zürich, 8093, Zürich, Switzerland;
    4 Department of Physics, Beijing University of Posts and Telecommunications, Beijing 100876, China
  • Received:2020-06-06 Revised:2020-06-12 Accepted:2020-06-23 Online:2020-09-05 Published:2020-09-05
  • Contact: Pei-Gang Li, Hong Xiao E-mail:pgli@bupt.edu.cn;hong.xiao@hpstar.ac.cn
  • Supported by:
    Project supported by NSAF, China (Grant No. U1530402). P. G. Li acknowledges the support of the National Natural Science Foundation of China (Grant No. 51572241).

摘要: Torque measurements were performed on single crystal samples of Ca0.73La0.27(Fe0.96Co0.04)As2 in both the normal and superconducting states. Contributions to the torque signal from the paramagnetism and the vortex lattice were identified. The superconducting anisotropy parameter γ was determined from the reversible part of the vortex contribution based on Kogan's model. It is found that γ ≈ 7.5 at t=T/Tc=0.85, which is smaller than the result of CaFe0.88Co0.12AsF γ ≈ 15 at t=0.83, but larger than the result of 11 and 122 families, where γ stays in the range of 2-3. The moderate anisotropy of this 112 iron-based superconductor fills the gap between 11, 122 families and 1111 families. In addition, we found that the γ shows a temperature dependent behavior, i.e., decreasing with increasing temperature. The fact that γ is not a constant point towards a multiband scenario in this compound.

关键词: torque, anisotropy parameter, superconductivity

Abstract: Torque measurements were performed on single crystal samples of Ca0.73La0.27(Fe0.96Co0.04)As2 in both the normal and superconducting states. Contributions to the torque signal from the paramagnetism and the vortex lattice were identified. The superconducting anisotropy parameter γ was determined from the reversible part of the vortex contribution based on Kogan's model. It is found that γ ≈ 7.5 at t=T/Tc=0.85, which is smaller than the result of CaFe0.88Co0.12AsF γ ≈ 15 at t=0.83, but larger than the result of 11 and 122 families, where γ stays in the range of 2-3. The moderate anisotropy of this 112 iron-based superconductor fills the gap between 11, 122 families and 1111 families. In addition, we found that the γ shows a temperature dependent behavior, i.e., decreasing with increasing temperature. The fact that γ is not a constant point towards a multiband scenario in this compound.

Key words: torque, anisotropy parameter, superconductivity

中图分类号:  (Magnetic properties including vortex structures and related phenomena)

  • 74.25.Ha
74.25.Op (Mixed states, critical fields, and surface sheaths) 74.70.Xa (Pnictides and chalcogenides)