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arXiv · 1310.5608

On the determination of the quasiparticle scattering rate in unconventional superconductors by microwave surface impedance

N. T. Cherpak·A. A. Barannik·R. Prozorov·M. Tanatar·A. V. Velichko
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Abstract

In the approximation of validity of the Drude expression for quasiparticle conductivity and the assumption that all electrons at T = 0 transform into a superfluide condensate, the expression for the quasiparticle scattering rate tau -1 in terms of the real and imaginary parts of the microwave surface impedance has been obtained. The resulting expression is a generalization of the well-known expression for tau^-1, valid for omega x tau is much less 1, to an arbitrary value of omega x tau, where omega is the frequency of the microwave field. From experimental Ka-band impedance measurements, temperature dependence of tau^-1 in superconducting single crystal pnictides Ba(Fe1-xCox)2As2 is obtained using the generalized expression. It is shown that under condition of the given work, the approximation omega x tau is much less 1 gives the considerable error in determination of tau^-1.

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N. T. Cherpak, A. A. Barannik, R. Prozorov, M. Tanatar, A. V. Velichko. 2013-10-21. On the determination of the quasiparticle scattering rate in unconventional superconductors by microwave surface impedance. https://doi.org/10.1063/1.4830422

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