Superconducting Transition and Phase Diagram of Single Crystal MgB2

Abstract

The superconducting phase diagram of MgB2 was determined from magnetization, magneto-transport and the first single-crystal specific heat measurements. A zero-temperature in-plane coherence length of 8 nm is determined. The superconducting anisotropy increases from a value around 2 near Tc to above 4.5 at 22 K. For H||c a pronounced peak effect in the critical current occurs at the upper critical field. Evidence for a surface superconducting state is presented for H||c which might account for the wide spread in reported values of the anisotropy.

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Cited by in corpus (31)

• Enhancement of the upper critical field by nonmagnetic impurities in dirty two-gap superconductors
• Carbon substitution in MgB2 single crystals: structural and superconducting properties
• Probing multiband superconductivity by point-contact spectroscopy
• Upper critical field in dirty two-band superconductors: breakdown of the anisotropic Ginzburg-Landau theory
• Al substitution in MgB2 crystals: influence on superconducting and structural properties
• Anisotropies of the lower and upper critical fields in MgB${}_2$ single crystals
• Pressure dependence of the upper critical field of MgB2 and of YNi2B2C
• Influence of the upper critical field anisotropy on the transport properties of polycrystalline MgB${}_2$
• Fate of the Peak Effect in a Type-II Superconductor: Multicriticality in the Bragg-Glass Transition
• Two-band Effects in the Angular Dependence of Hc2 of MgB2 Single Crystals
• Super-conducting critical fields and anisotropy of a MgB2 single crystal
• Thermally-activated current transport in MgB_2 films
• Surface Contribution to the Superconducting Properties of MgB2 Single Crystals
• Influence of Al doping on the critical fields and gap values in magnesium diboride single crystals
• From the second magnetization peak to peak effect. A study of superconducting properties in Nb films and MgB2 bulk samples
• MgB2 single crystals substituted with Li and with Li-C: Structural and superconducting properties
• Reversible magnetization of MgB2 single crystals with a two-gap nature
• Phase transition between the Bragg Glass and a disordered Phase in Nb3Sn, detected by 3rd harmonics of the AC magnetic susceptibility
• Influence of randomly distributed magnetic nanoparticles on surface superconductivity in Nb films
• Reversible magnetization measurement of the anisotropy of the London penetration depth in MgB2 single crystals
• Ab initio calculations of H${}_{c2}$ for Nb, NbSe2, and MgB2
• Effects of the Two- Gap Nature on the Microwave Conductivity of 39 K Polycrystalline MgB2 Films
• Superconducting properties of Rh${}_9$In${}_4$S${}_4$ single crystals
• Puzzling evidence for surface superconductivity in the layered dichalcogenide Cu${}_{10\%}$TiSe${}_2$
• Non-gapless excitation and zero-bias fast oscillations in the LDOS of surface superconducting states
• Vortex-glass transformation within the surface superconducting state of $\beta$-phase Mo${}_{1-x}$Re${}_x$ alloys
• Surface superconducting states in a polycrystalline MgB${}_2$ sample
• The influence of weak texture on the critical currents in polycrystalline MgB${}_2$
• Superconductivity of Magnesium Diboride: Theoretical Aspects
• High-pressure high-temperature solution growth, structural, and superconducting properties of Fe-substituted MgB2 single crystals
• Comment on "Superconducting anisotropy and evidence for intrinsic pinning in single crystalline MgB2"