Magnetic properties of melt processed YBaCuO by micro Hall probe

Magnetic properties of a melt-processed YBaCuO superconductor were studied by using a microsize Hall probe. A bulk of YBaCuO superconductor, 30 mm/spl times/30 mm/spl times/1.9 mm, with a high critical current density at 77 K was prepared by the melt process. Two-dimensional distributions of the local magnetic induction, B/sub t/ over the surface of the YBaCuO superconducting plate, were measured at 77 K, when a magnetic field up to 100 mT was applied perpendicular to the sample surface. The distribution of the local magnetic induction indicates the magnetic shielding effect when the external magnetic field is applied. By using the microsize Hall probe with an active area of 50 /spl mu/m/spl times/50 /spl mu/m, the inhomogeneous distribution of the local magnetic induction due to the existence of a weak link region was observed. External magnetic field dependence of B/sub t/ at several positions was also measured in perpendicular magnetic fields of up to 1.4 T. The magnetization process on these positions of the YBaCuO superconductor clearly indicated the behavior of the critical state and the edge effect.