Microwave absorption study of pinning regimes in $\bf Ba(Fe_{1-x}Co_x)_2As_2$ single crystals

Yu. Talanov; N. Beisengulov; G. Kornilov; T. Shaposhnikova; E. Vavilova; C. Nacke; S. Wurmehl; N. Panarina; C. Hess; V. Kataev; B. Büchner

doi:10.1088/0953-2048/26/4/045015

arXiv · 1210.2309

Microwave absorption study of pinning regimes in $\bf Ba(Fe_{1-x}Co_x)_2As_2$ single crystals

Yu. Talanov·N. Beisengulov·G. Kornilov·T. Shaposhnikova·E. Vavilova·C. Nacke·S. Wurmehl·N. Panarina·C. Hess·V. Kataev·B. Büchner

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Abstract

Magnetic field dependent modulated microwave absorption (MMWA) measurements have been carried out to investigate vortex pinning effects in single crystals of the iron-based high-Tc superconductor Ba(Fe_{1-x}Co_x)_2As_2 with three different cobalt doping levels of x = 0.07, 0.09, and 0.11. The dependence of the MMWA hysteresis loops on temperature, magnetic field, and Co-concentration have been measured and analyzed using a theoretical model of microwave absorption in superconductors. The analysis reveals that in an underdoped crystal (x = 0.07) the so called \dtc-pinning due to magnetically ordered regions defines the temperature dependence of the critical current density, while in the optimally doped (x = 0.09) and overdoped (x = 0.11) samples the pinning is governed by structural imperfections due to inhomogeneous distribution of cobalt dopant and has the so called δ-l character.

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Yu. Talanov, N. Beisengulov, G. Kornilov, T. Shaposhnikova, E. Vavilova, C. Nacke, S. Wurmehl, N. Panarina, C. Hess, V. Kataev, B. Büchner. 2012-10-08. Microwave absorption study of pinning regimes in $\bf Ba(Fe_{1-x}Co_x)_2As_2$ single crystals. https://doi.org/10.1088/0953-2048%2F26%2F4%2F045015

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