Audouard A, Drigo L, Duc F, Fabrèges X, Bosseaux L, Toulemonde P
Laboratoire National des Champs Magnétiques Intenses (UPR 3228 CNRS, INSA, UJF, UPS) 143 avenue de Rangueil, F-31400 Toulouse, France.
J Phys Condens Matter. 2014 May 7;26(18):185701. doi: 10.1088/0953-8984/26/18/185701. Epub 2014 Apr 14.
Temperature dependence of the upper critical magnetic field (Hc2) of single crystalline FeTe0.5Se0.5(Tc = 14.5 K) have been determined by tunnel diode oscillator-based measurements in magnetic fields of up to 55 T and temperatures down to 1.6 K. The Werthamer-Helfand-Hohenberg model accounts for the data for magnetic field applied both parallel (H ‖ ab) and perpendicular (H ‖ c) to the iron conducting plane, in line with a single band superconductivity. Whereas Pauli pair breaking is negligible for H ‖ c, Pauli contribution is evidenced for H ‖ ab with Maki parameter α = 1.4, corresponding to Pauli field HP = 79 T. As a result, the Hc2 anisotropy [Formula: see text] which is already rather small at Tc (γ = 1.6) further decreases as the temperature decreases and becomes smaller than 1 at liquid helium temperatures.
通过基于隧道二极管振荡器的测量，在高达55 T的磁场和低至1.6 K的温度下，确定了单晶FeTe0.5Se0.5（Tc = 14.5 K）的上临界磁场（Hc2）的温度依赖性。韦瑟默-赫尔方德-霍亨贝格模型解释了平行（H ‖ ab）和垂直（H ‖ c）于铁导电平面施加磁场时的数据，这与单带超导性一致。对于H ‖ c，泡利对破坏可忽略不计，而对于H ‖ ab，泡利贡献明显，马基参数α = 1.4，对应泡利场HP = 79 T。结果，Hc2各向异性[公式：见正文]在Tc时已经相当小（γ = 1.6），随着温度降低进一步减小，在液氦温度下变得小于1。
