Anisotropic Superconducting Properties of MgB2 Single Crystals

Abstract

In-plane electrical transport properties of MgB2 single crystals grown under high pressure of 4-6 GPa and temperature of 1400-1700oC in Mg-B-N system have been measured. For all specimens we found sharp superconducting transition around 38.1-38.3K with transition width within 0.2-0.3K. Estimated resistivity value at 40K is about 1 mkOhmcm and resistivity ratio R(273K)/R(40K) of about 4.9. Results of measurements in magnetic field up to 5.5T perpendicular to Mg and B planes and up to 9T in parallel orientation show temperature dependent anisotropy of the upper critical field with anisotropy ratio increasing from 2.2 close to Tc up to about 3 below 30K. Strong deviation of the angular dependence of Hc2 from anisotropic mass model has been also found.

10pages, including 5 figures,submitted to Physica C (in press)

References in corpus (11)

• Superconductivity of metallic boron in MgB_2
• Strongly linked current flow in polycrystalline forms of the new superconductor MgB2
• Boron Isotope Effect in Superconducting MgB${}_2$
• Specific Heat of Mg ^{11}B_2
• Thermodynamic and Transport Properties of Superconducting $M{g}^{10}{B}_2$
• Superconducting Properties of MgB2 Bulk Materials Prepared by High Pressure Sintering
• Growth, structure analysis and anisotropic superconducting properties of MgB2 single crystals
• Electronic anisotropy, magnetic field-temperature phase diagram and their dependence on resistivity in c-axis oriented MgB2 thin films
• Magnetoresistivity and Complete $H_{c2}(T)$ in $Mg{B}_2$
• Anisotropic superconducting properties of aligned MgB2 crystallites
• Upper critical field and irreversibility line in superconducting MgB_2

Cited by in corpus (6)

• Upper critical field in dirty two-band superconductors: breakdown of the anisotropic Ginzburg-Landau theory
• Dependence of the superconducting transition temperature of single- and polycrystalline MgB2 on hydrostatic pressure
• Two-band Effects in the Angular Dependence of Hc2 of MgB2 Single Crystals
• Surface Contribution to the Superconducting Properties of MgB2 Single Crystals
• Theory of fluctuations in a two-band superconductor
• The Upper Critical Field Hc2 in Advanced Superconductors with Anisotropic Energy Spectrum