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Exponential Temperature Dependence of Penetration Depth in Single Crystal MgB_2

F. Manzano·A. Carrington·N. E. Hussey·S. Lee·A. Yamamoto
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Abstract

The temperature dependence of the London penetration depth,lambda(T), was measured in both single crystal and polycrystalline MgB_2 samples by a high-resolution, radio frequency technique. A clear exponential temperature dependence of lambda(T) was observed at low temperature, indicating s-wave pairing. A BCS fit to the lowest temperature data gives an in-plane energy gap Delta of 2.6\pm0.2 meV (2Δ/T_c=1.5\pm0.1), which is significantly smaller than the standard BCS weak coupling value of 3.5. We find that the data are best described by a two-gap model.

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F. Manzano, A. Carrington, N. E. Hussey, S. Lee, A. Yamamoto. 2002-01-08. Exponential Temperature Dependence of Penetration Depth in Single Crystal MgB_2. https://doi.org/10.1103/physrevlett.88.047002

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