Improvement of critical current density in the Cu/MgB2 and Ag/MgB2 superconducting wires using the fast formation method

Abstract

The powder in tube method has been used to fabricate Ag and Cu clad MgB2 wires using an in-situ reaction method. The effects of short time sintering on the critical current densities of Ag and Cu clad MgB2 wires were studied. All the samples were examined using XRD, SEM, and magnetization measurements. For Ag clad wire Jc is improved by more than two times after the short time sintering process. Jc values of 1.2x10^5 A/cm2 in zero field and above 10^4 A/cm2 in 2T at 20 K have been achieved for Ag clad MgB2 wire which is only sintered for 6 minutes at 800oC. However, a remarkable degree of reaction has been found between the superconducting cores and the sheath materials, leading to the formation of Cu2Mg and Ag3Mg for copper and silver clad wires, respectively. The results from Tc, Jc and Hirr convincingly show that the short sintering causes less reaction between the magnesium and the sheath materials and markedly improves the critical current density. Our result shows that Iron is still the best sheath material because of the lack of reaction between Fe and the superconducting MgB2 material.

18 pages, 11 figures, submitted to Supercond. Sci. & Technol. on Dec. 16, 2001

References in corpus (10)

• Strongly linked current flow in polycrystalline forms of the new superconductor MgB2
• Superconductivity in Dense $Mg{B}_2$ Wires
• Large transport critical currents in unsintered MgB2 superconducting tapes
• Large transport critical currents in dense Fe- and Ni-clad MgB2 superconducting tapes
• High transport critical current density above 30 K in pure Fe-clad MgB2 tape
• Very fast formation of superconducting MgB2/Fe wires with high Jc
• Improvement of critical current in MgB2/Fe wires by a ferromagnetic sheath
• Flux Jumping and a Bulk-to-Granular Transition in the Magnetization of a Compacted and Sintered MgB2 Superconductor
• Superconducting properties of the powder-in-tube Cu-Mg-B and Ag-Mg-B wires
• Evidence for high inter-granular current flow in single-phase polycrystalline MgB2 superconductor

Cited by in corpus (3)

• Sonochemical Modification of the Superconducting Properties of MgB2
• MgB2 coated superconducting tapes with high critical current densities fabricated by hybrid physical-chemical vapor deposition
• The Electronic and Superconducting Properties of Oxygen-Ordered MgB2 compounds of the form Mg2B3Ox