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arXiv · 0801.0269

Two-gap superconductivity in single crystal Lu$_2$Fe$_3$Si$_5$ from penetration depth measurements

R. Gordon·M. D. Vannette·C. Martin·Y. Nakajima·T. Tamegai·R. Prozorov
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Abstract

Single crystal of Lu$_2$Fe$_3$Si$_5$ was studied with the tunnel-diode resonator technique in Meissner and mixed states. Temperature dependence of the superfluid density provides strong evidence for the two-gap superconductivity with almost equal contributions from each gap of magnitudes $Δ_1/k_BT_c=1.86$ and $Δ_1/k_BT_c=0.54$. In the vortex state, pinning strength shows unusually strong temperature dependence and is non-monotonic with the magnetic field (peak effect). The irreversibility line is sharply defined and is quite distant from the $H_{c2}(T)$, which hints on to enhanced vortex fluctuations in this two-gap system. Altogether our findings provide strong electromagnetic - measurements support to the two-gap superconductivity in Lu$_2$Fe$_3$Si$_5$ previously suggested from specific heat measurements.

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R. Gordon, M. D. Vannette, C. Martin, Y. Nakajima, T. Tamegai, R. Prozorov. 2008-01-01. Two-gap superconductivity in single crystal Lu$_2$Fe$_3$Si$_5$ from penetration depth measurements. https://doi.org/10.1103/physrevb.78.024514

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