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arXiv · 1708.00683

Dependence of the absolute value of the penetration depth in $\mathrm{\mathbf{{(Ba_{1-x}K_x)Fe_2As_2}}}$ on doping

Avior Almoalem·Alon Yagil·Kyuil Cho·Serafim Teknowijoyo·Makariy A. Tanatar·Ruslan Prozorov·Yong Liu·Thomas A. Lograsso·Ophir M. Auslaender
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Abstract

We report magnetic force microscopy (MFM) measurements on the iron-based superconductor $\mathrm{Ba_{1-x}K_xFe_2As_2}$. By measuring locally the Meissner repulsion with the magnetic MFM tip, we determine the absolute value of the in-plane magnetic penetration depth ($λ_{ab}$) in underdoped, optimally-doped, and overdoped samples. The results suggest an abrupt increase of $λ_{ab}$ as doping is increased from $x_\mathrm{opt}$, which is potentially related to the presence of a quantum critical point. The response of superconducting vortices to magnetic forces exerted by the MFM tip for $x=0.19$ and $0.58$ is compatible with previously observed structural symmetries at those doping levels.

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Avior Almoalem, Alon Yagil, Kyuil Cho, Serafim Teknowijoyo, Makariy A. Tanatar, Ruslan Prozorov, Yong Liu, Thomas A. Lograsso, Ophir M. Auslaender. 2018-10-15. Dependence of the absolute value of the penetration depth in $\mathrm{\mathbf{{(Ba_{1-x}K_x)Fe_2As_2}}}$ on doping. https://doi.org/10.1103/physrevb.98.054516

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