Modification of critical current density of MgB 2 films irradiated with 200 MeV Ag ions

The modification in the temperature and field dependence of critical current density of high quality MgB 2 thin films, irradiated with 200 MeV Ag ion, was studied. A standard four-probe technique with a direct current source was used for transport measurements. Significant enhancement in critical current density, in a specific magnetic field range, was observed for MgB 2 films. The formation of defect clusters in high concentration is suggested to be responsible for the observed improvement in J C.