Direct visualization of iron sheath shielding effect in MgB_2 superconducting wires

Abstract

Local magneto-optical imaging and global magnetization measurement techniques were used in order to visualize shielding effects in the superconducting core of MgB_2 wires sheathed by ferromagnetic iron (Fe). The magnetic shielding can provide a Meissner-like state in the superconducting core in applied magnetic fields up to ~1T. The maximum shielding fields are shown to correlate with the saturation fields of magnetization in Fe-sheaths. The shielding has been found to facilitate the appearance of an overcritical state, which is capable of achieving a critical current density (J_c) in the core which is larger than J_c in the same wire without the sheath by a factor of ~2. Other effects caused by the magnetic interaction between the sheath and the superconducting core are discussed.

4 pages, 3 figures

References in corpus (4)

• Thermodynamic and Transport Properties of Superconducting $M{g}^{10}{B}_2$
• High transport critical current density above 30 K in pure Fe-clad MgB2 tape
• Overcritical states of a superconductor strip in a magnetic environment
• Improvement of critical current in MgB2/Fe wires by a ferromagnetic sheath

Cited by in corpus (8)

• Properties of superconducting MgB_2 wires: "in-situ" versus "ex-situ" reaction technique
• Overcritical state in superconducting round wires sheathed by iron
• Entry of magnetic flux into a magnetically shielded type-II superconductor filament
• The Bean-Livingston barrier at a superconductor/magnet interface
• Critical State Theory For The Magnetic Coupling Between Soft Ferromagnetic Materials And Type-II Superconductors
• A new approach to the inverse problem for current mapping in thin-film superconductors
• The Bean model of the critical state in a magnetically shielded superconductor filament
• Magneto-optical investigations of Ag-sheathed Bi-2223 tapes with ferromagnetic shielding