| Popis: |
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/T c = 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. |
