【摘要】 磁场穿透深度λ是超导体的一个基本参数，目前，一般测试穿透深度的实验只能给出其变化量Δλ＝λ（Ｔ）－λ（０），而不能得到λ的绝对值．并且由于测量精度的限制，用给定的理论模型拟合实验结果而得到的λ也有很大的不确定性．本文对此进行了详细的分析，并用双线圈互感法研究了超导薄膜穿透深度的精确测量，并给出了磁控溅射Ｎｂ膜的测量结果．我们的研究表明，这一方法能较为准确地给出λ的绝对值，从而避免了以往的测量及拟合所导致的不确定性．基于ＢＣＳ理论并考虑样品有限的电子平均自由程后，理论计算结果与我们的测量结果吻合较好更多还原

【Abstract】 AbstractMagnetic penetration depth λ is a fundamental parameter of superconductors. Most of the experimental methods used to measure this quality so far are only sensitive to the change of λ . As a result, a particular theory is required to determine its absolute value, and different theories often lead to different values of λ . As a result, a particular theory is required to determine its absolute value, and different theories often lead to different values of λ . In this work, we discuss these aspects and demonstrate an accurate measurement of λ made possible by an optimized two coil mutual inductance apparatus. Our data obtained with magnetron sputtered Nb films are found to be well described by the existing theory that takes a finite electronic mean free path into account.更多还原