Connectivity and Critical Currents in Polycrystalline MgB2

Abstract

Current transport in polycrystalline magnesium diboride is highly non-uniform (percolative) due to the presence of secondary phases and also due to the intrinsic anisotropy of the material. The influence of secondary phases on the transport properties of MgB2 was investigated. Bulk samples were prepared from a mixture of MgB2 and MgO powders by the ex-situ technique in order to vary the MgO content systematically. The samples were characterized by resistive and magnetization measurements. The reduced MgB2 fraction is modeled by a reduced effective cross section (connectivity), which was assessed directly by the experiments. The presence of MgO also increases the percolation threshold, which reduces the zero resistivity (or irreversibility) field.

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Cited by in corpus (4)

• Anisotropic Connectivity and its Influence on Critical Current Densities, Irreversibility Fields, and Flux Creep in In-Situ-Processed MgB2 Strands
• Disorder effects and current percolation in FeAs based superconductors
• Critical currents in weakly textured MgB2: Nonlinear transport in anisotropic heterogeneous media
• The influence of weak texture on the critical currents in polycrystalline MgB${}_2$