Magnetic characterization of superconducting MgB2

The critical current density J(c) of pressed polycrystalline MgB2 specimen was measured using a DC magnetization and Campbell's method. It was found that the two J(c)s are coincident and this result confirms that the intergrain J(c) is not deteriorated by grain boundaries. The upper critical field, lower critical field, thermodynamic critical field and Ginzburg Landau parameter were estimated to characterize the magnetic properties. Observed J(c) and irreversibility field could be approximately explained by the flux creep-flow model. To foresee the potential of application of this material, J(c) was calculated when strong pins could be introduced. (C) 2002 Published by Elsevier Science B.V.