Modification of flux pinning properties of RE-Ba-Cu-O superconductor by irradiation

The effects of fast neutron irradiation and heavy-ion irradiation on the magnetization of RE-Ba-Cu-O single crystals were studied. The fast neutron irradiation introduces spherical cascade defects, whereas the heavy-ion irradiation creates columnar defects which penetrate throughout the sample. In both cases, we observed the enhancement of the magnetic hysteresis width and the reduction of the normalized creep rate, which implies the induced defects work effectively as pinning centres. However, we found there are some differences in the magnetization behaviour between the neutron-irradiated and the heavy-ion-irradiated samples, which may be explained in terms of differences in the defect morphology.