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 ma gnetization of RE-Ba-Cu-O single crystals were studied. The fast neutron ir radiation introduces spherical cascade defects, whereas the heavy-ion irrad iation creates columnar defects which penetrate throughout the sample. In b oth cases, we observed the enhancement of the magnetic hysteresis width and the reduction of the normalized creep rate, which implies the induced defe cts work effectively as pinning centres. However, we found there are some d ifferences in the magnetization behaviour between the neutron-irradiated an d the heavy-ion-irradiated samples, which may be explained in terms of diff erences in the defect morphology.