Critical current density analysis of ex situ MgB2 wire by in-field and temperature Hall probe imaging
Abstract:The irreversible magnetic behaviour at different temperatures of an ex situ Fe-alloy/MgB2 wire, exhibiting a granular compositional distribution, was studied using an in-field, high resolution Hall probe imaging system. Quantitative information about the local current density was obtained by solving the Biot–Savart inversion problem. The flux penetration and current distribution maps obtained can be attributed to a inhomogeneous compositional 'plum-cake-like' system, consisting of large, isolated MgB2 agglomerations embedded in a matrix of finely distributed MgB2+MgO. The critical current densities within the grains and their evolution with the applied magnetic field and temperature have been obtained, and compared to the mean Jc(H,T) in the matrix.
Document Type: Research Article
Publication date: August 1, 2005