Penetration Depth Measurements in MgB_2: Evidence for Unconventional Superconductivity

Abstract

We have measured the magnetic penetration depth of the recently discovered binary superconductor MgB_2 using muon spin rotation and low field $ac$-susceptibility. From the damping of the muon precession signal we find the penetration depth at zero temperature is about 85nm. The low temperature penetration depth shows a quadratic temperature dependence, indicating the presence of nodes in the superconducting energy gap.

4 pages 3 figures

References in corpus (5)

• Scanning Tunneling Spectroscopy in MgB2
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Cited by in corpus (25)

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• Energy gap, penetration depth and surface resistance of MgB2 thin films determined by microwave resonator mesurements
• RVB Contribution to Superconductivity in $Mg{B}_2$
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• Quasiparticle Excitations outside the Vortex Cores in MgB${}_2$ Probed by Muon Spin Rotation
• Strongly Anisotropic s-Wave Gaps in Exotic Superconductors
• Energy gap and proximity effect in $Mg{B}_2$ superconducting wires
• muSR study of carbon-doped MgB2 superconductors
• A Magnetization and Microwave Study of Superconducting MgB2
• Characteristic features of the temperature dependence of the surface impedance in polycrystalline MgB${}_2$ samples
• Grain size determination of superconducting MgB2 powders from magnetization curve, image analysis and surface area measurement
• Heat capacity of mesoscopically disordered superconductors:implications to MgB${}_2$
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• Electrodynamic response of MgB2 sintered pellets and thin films
• Probing superconductivity in MgB2 confined to magnetic field tuned cylinders by means of critical fluctuations
• The study on penetration depth of anisotropic two-band s-wave superconductors by Ginzburg-Landau approach