Superconducting fluctuations in Bi2Sr2Ca2Cu3Ox thin films: Paraconductivity, excess Hall effect, and magnetoconductivity.
Superconducting fluctuations in Bi2Sr2Ca2Cu3Ox thin films: Paraconductivity, excess Hall effect, and magnetoconductivity.
复制标题
Bi2Sr2Ca2Cu3Ox 薄膜中的超导涨落：顺导性、过量霍尔效应和磁导性。
DOI：
10.1103/physrevb.51.9180
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发表时间：
1995
期刊：
影响因子：
--
通讯作者：
Sobolewski
中科院分区：
文献类型：
--
作者：
Lang;Heine;Kula;Sobolewski
详细研究了通过直流磁控溅射在 MgO 基底上制备的零电阻临界温度 [ital T][sub [ital c]0]=105 K 的 (Bi,Pb)[sub 2]Sr[sub 2]Ca[sub 2]Cu[sub 3]O[sub [ital x]] 薄膜的常态磁输运特性。使用二维层状超导体理论，分析了电阻率、磁阻和霍尔效应的测量对超导有序参数热力学涨落的贡献。我们得到了一组一致的参数，即面内相干长度[xi][sub [ital a][ital b]](0)=1.6 nm，面外相干长度[xi][sub [ital c]](0)=0.14 nm，电子空穴不对称参数β=[minus]0.38。在低于 118 K 的温度下，我们观察到过量霍尔效应和磁导率均显着增强（高于理论预测），而零场顺导率则没有检测到这种效应。上述异常现象归因于我们样品内部的不均匀临界温度分布，并且可以很好地解释假设[ital T][sub [ital c]]的高斯分布，标准差为δ[ital T][sub [ital c]]=2.3 K。超导波动引起的过量霍尔效应在整个可及的温度范围内为负，这表明，与顺导性和磁导性一起导致间接（Maki-Thompson）波动(Bi,Pb)[sub 2]Sr[sub 2]Ca[submore » 2]Cu[sub 3]O[sub [ital x]] 的过程在 [ital T][sub [ital c]] 至 130 K 的温度范围内微乎其微。« less
A detailed study of normal-state magnetotransport properties in (Bi,Pb)[sub 2]Sr[sub 2]Ca[sub 2]Cu[sub 3]O[sub [ital x]] thin films with a zero-resistance critical temperature [ital T][sub [ital c]0]=105 K prepared by dc-magnetron sputtering on MgO substrates is reported. Measurements of the electrical resistivity, the magnetoresistance, and the Hall effect are analyzed with regard to contributions of the superconducting order-parameter thermodynamic fluctuations, using theories for two-dimensional, layered superconductors. We have obtained a consistent set of parameters, i.e., the in-plane coherence length [xi][sub [ital a][ital b]](0)=1.6 nm, the out-of-plane coherence length [xi][sub [ital c]](0)=0.14 nm, and the electron-hole asymmetry parameter [beta]=[minus]0.38. At temperatures below 118 K, we observe a remarkable enhancement (above theoretical predictions) of both the excess Hall effect and magnetoconductivity, whereas no such effect is detected for the zero-field paraconductivity. The above anomalies are attributed to a nonuniform critical temperature distribution inside our samples and can be well explained assuming a Gaussian distribution of [ital T][sub [ital c]]'s with a standard deviation [delta][ital T][sub [ital c]]=2.3 K. The excess Hall effect caused by superconducting fluctuations is negative in the entire accessible temperature range, which indicates, together with the paraconductivity and magnetoconductivity results that the indirect (Maki-Thompson) fluctuation process for (Bi,Pb)[sub 2]Sr[sub 2]Ca[submore » 2]Cu[sub 3]O[sub [ital x]] is vanishingly small at temperatures from [ital T][sub [ital c]] to 130 K.« less