S-wave superconductivity probed by measuring magnetic penetration depth and lower critical field of MgCNi$_{3}$ single crystals

P. Diener; Pierre Rodiere; Thierry Klein; Christophe Marcenat; Jozef Kacmarcik; Zuzana Pribulova; D. J. Jang; H. S. Lee; H. G. Lee; S. I. Lee

doi:10.1103/physrevb.79.220508

arXiv · 1301.1879

S-wave superconductivity probed by measuring magnetic penetration depth and lower critical field of MgCNi$_{3}$ single crystals

P. Diener·Pierre Rodiere·Thierry Klein·Christophe Marcenat·Jozef Kacmarcik·Zuzana Pribulova·D. J. Jang·H. S. Lee·H. G. Lee·S. I. Lee

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Abstract

The magnetic penetration depth $\lambda$ has been measured in MgCNi$_{3}$ single crystals using both a high precision Tunnel Diode Oscillator technique (TDO) and Hall probe magnetization (HPM). In striking contrast to previous measurements in powders, $\delta\lambda$(T) deduced from TDO measurements increases exponentially at low temperature, clearly showing that the superconducting gap is fully open over the whole Fermi surface. An absolute value at zero temperature $\lambda(0)=230 $nm is found from the lower critical field measured by HPM. We also discuss the observed difference of the superfluid density deduced from both techniques. A possible explanation could be due to a systematic decrease of the critical temperature at the sample surface.

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P. Diener, Pierre Rodiere, Thierry Klein, Christophe Marcenat, Jozef Kacmarcik, Zuzana Pribulova, D. J. Jang, H. S. Lee, H. G. Lee, S. I. Lee. 2013-01-09. S-wave superconductivity probed by measuring magnetic penetration depth and lower critical field of MgCNi$_{3}$ single crystals. https://doi.org/10.1103/physrevb.79.220508

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