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arXiv 0708.2602cond-mat.supr-con
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电阻态超窄超导纳米线的负磁阻效应

Negative magnetoresistance of ultra-narrow superconducting nanowires in the resistive state

K. Yu. Arutyunov

摘要:

本文提出了一个定性解释准一维超导沟道中电阻态负磁阻现象的唯象模型。该模型是基于这样的假设,即序参量(相位滑移)的波动是负责有限的有效电阻的窄超导导线充分接近的临界温度。每个波动都伴随着一个准正常区域的顺序的非平衡准粒子弛豫长度的“钉扎”的相滑移的核心的瞬间形成。实验测得的有效时均电压是两项之和。第一个是通过约瑟夫森关系与涨落率相联系的常规贡献。第二项是该准正常区域的欧姆贡献。根据导线的材料特性,可能存在第一项不受太大影响的磁场范围,而第二项被有效抑制,从而有助于实验观察到的负磁阻。

英文摘要:

We present a phenomenological model qualitatively explaining negative magnetoresistance in quasi-one-dimensional superconducting channels in the resistive state. The model is based on the assumption that fluctuations of the order parameter (phase slips) are responsible for the finite effective resistance of a narrow superconducting wire sufficiently close to the critical temperature. Each fluctuation is accompanied by an instant formation of a quasi-normal region of the order of the non-equilibrium quasiparticle relaxation length 'pinned' to the core of the phase slip. The effective time-averaged voltage measured in experiment is a sum of two terms. First one is the conventional contribution linked to the rate of the fluctuations via the Josephson relation. Second term is the Ohmic contribution of this quasi-normal region. Depending on material properties of the wire, there might be a range of magnetic fields where the first term is not much affected, while the second term is effectively suppressed contributing to the experimentally observed negative magnetoresistance.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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