Anisotropy of superconducting MgB2 as seen in electron spin resonance and magnetization data

Abstract

We have observed the conduction electron spin resonance (CESR) in fine powders of MgB2 both in the superconducting and normal states. The Pauli susceptibility is chi_s=2.0*10^{-5} emu/mole in the temperature range of 450 to 600 K. The spin relaxation rate has an anomalous temperature dependence. The CESR measured below T_c at several frequencies suggests that MgB_2 is a strongly anisotropic superconductor with the upper critical field, H_c2, ranging between 2 and 16 T. The high-field reversible magnetization data of a randomly oriented powder sample are well described assuming that MgB_2 is an anisotropic superconductor with H_c2^{ab} / H_{c2}^{c} \approx 6--9.

4 pages, 4 eps figures

References in corpus (7)

• Superconductivity of metallic boron in MgB_2
• Boron Isotope Effect in Superconducting MgB${}_2$
• Superconductivity in Dense $Mg{B}_2$ Wires
• Thermodynamic and Transport Properties of Superconducting $M{g}^{10}{B}_2$
• 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

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