Modification of critical current density of MgB_(2) films irradiated with 200 MeV Ag ions

摘要

The effect of 200 MeV Ag ion irradiation on the temperature and field dependence of critical current density (J_(C)) of high quality MgB_(2) thin films is studied. Substantial increase in J_(C) is observed over a certain field range for the film irradiated at a dose of 10~(12) ions/cm~(2). Our analysis suggests that columnar defects are not formed under irradiation conditions used in these studies, which correspond to an electronic energy loss of about 16 keVm. Defects clusters are likely to be responsible for the observed improvement in J_(C).