Neutron irradiation effect on magnetization and thermal conductivity of (Hg/sub 1-x/Bi/sub x/)Ba/sub 2/Ca/sub 2/Cu/sub 3/O/sub y/ superconductor

We have investigated the neutron irradiation effect on a phase-pure (Hg/sub 1-x/Bi/sub x/)Ba/sub 2/Ca/sub 2/Cu/sub 3/O/sub y/ superconductor through magnetization and thermal conductivity measurements. It has been found that the inclusion of point-defects from the irradiation lowers the transition temperature and destroys the coupling between neighboring superconducting grains. Such point-defects act as strong flux pinning sites in the mixed state, resulting in the critical current density increase. The thermal conductivity data are used to study the scattering mechanisms between the heat carriers and the point defects in the absence and the presence of magnetic fields.