Tl_2Ba_2CaCu_2O_(8+δ)薄膜在超导凝聚过程中低频区的电磁响应

The evolution of electromagnetic response at low frequencies with the development of superconducting condensation in Tl_2Ba_2CaCu_2O_(8+δ)

研究了Tl2Ba2CaCu2O8+δ/LaAlO3单晶薄膜的ab平面内电子在超导凝聚过程中的行为,薄膜厚度为3000,转变温度Tc=96K。在凝聚过程中,阻抗谱z(ω,T0)变化剧烈。谱线随温度的变化规律与浅超导区直流压制下的阻抗谱极为相似。随着超导凝聚的加强,谱重从高频区进一步向低频区转移并且导致直流极限下的发散。通过分析,得出超导相变对应了"超流电子岛"从出现到扩大并最终连成"整片超导大陆"这样的过程。我们还测试了薄膜载流下的阻抗谱z(ω,B0),观测到临界电流密度随着超导凝聚的进行而增大。

We reported the ab-plane temperature dependent charge dynamics of Tl2Ba2CaCu2O8＋δ/LaAlO3（Tl-2212）single crystal films with thickness 3000 and Tc=96K.In process of the superconducting condensation,the impedance spectrum z（ω,T0）changed considerably.More over,it was very similar with the evolution of the spectrum under various dc bias in the shallow superconducting state.The spectrum weight transfered from high frequency regions to lower frequency range and eventually diverged towards the dc limit.From the analysis,the super fluid islands formed at the beginning and then grow larger,till the formation of a ＇continent＇.The impedance spectrum z（ω,B0）at various dc bias B0 was studied.