Fluctuation conductivity of electron-doped BaFe_1.9Co_0.1As₂ single crystal is investigated by measurement of electrical resistivity under magnetic fields up to 13 T at different angles of θ = 0̊, 45̊ and 90̊ near mean-field transition temperature, where θ is the angle between the applied magnetic field and the axis perpendicular to the ab plane. The mean-field transition temperature is determined using the peak of dR/dT curves. Using the Aslamazov–Larkin theory, four main regions are identified corresponding to 3D, 2D, 1D, and SW regions, respectively, for each angle at different magnetic fields. The 1D region is a sign of conducting charge strips that are believed that these 1D conducting strips might be responsible for the occurrence of high-temperature superconductivity. Anisotropy increases as it approaches T_c, suggesting unconventional superconductivity that might be due to multiband effects in crystal. Results show that the zero-temperature coherence length in the c-direction ξ(0), the effective distance between the conducting layers d, and the channel cross section s decrease with increase in the magnetic field.

中文翻译：

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BaFe 1.9 Co 0.1 As 2单晶中涨落电导率的角相关性

掺杂电子的BaFe _1.9 Co _0.1 As ₂单晶的波动电导率是通过在高达13 T的磁场中，在不同的θ  = 0°，45°和90°不同角度附近的平均场转变温度下测量电阻率来研究的，其中θ为施加的磁场和垂直于ab平面的轴之间的夹角。使用dR / dT的峰确定平均场转变温度 曲线。使用Aslamazov–Larkin理论，在不同磁场下，每个角度分别确定了四个主要区域，分别对应于3D，2D，1D和SW区域。1D区域是导电带的迹象，据信这些1D导电带可能是高温超导现象的原因。各向异性随着接近T _c的增加而增加 ，表明非常规超导性可能是由于晶体中的多带效应所致。结果表明，c方向ξ（0）上 的零温度相干长度，导电层之间的有效距离d和沟道截面s 随着磁场的增加而减小。