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arXiv · 0804.1726

Linear Temperature Dependence of the Lower Critical Field $H_{c1}$ in F-Doped LaOFeAs Superconductors

Cong Ren·Zhao-Sheng Wang·Huan Yang·Xiyu Zhu·Lei Fang·Gang Mu·Lei Shan·Hai-Hu Wen
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Abstract

We present the first experimental results of the lower critical field $H_{c1}$ of the newly discovered F-doped superconductor LaO$_{0.9}$F$_{0.1}$FeAs (F-LaOFeAs) by global and local magnetization measurements. It is found that $H_{c1}$ showed an clear linear-$T$ dependence down to a temperature of 2 K, indicative of an unconventional pairing symmetry with a nodal gap function. Based on the d-wave model, we estimated a maximum gap value $Δ_0=4.0 \pm 0.6$ meV, in consistent with the recent specific heat and point-contact tunneling measurements. Taking the demagnetization factor into account, the absolute value of $H_{c1}(0)$ is determined to be about 54 Oe, manifesting a low superfluid density for LaO$_{0.9}$F$_{0.1}$FeAs.

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Cong Ren, Zhao-Sheng Wang, Huan Yang, Xiyu Zhu, Lei Fang, Gang Mu, Lei Shan, Hai-Hu Wen. 2008-04-10. Linear Temperature Dependence of the Lower Critical Field $H_{c1}$ in F-Doped LaOFeAs Superconductors. https://arxiv.org/abs/0804.1726

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