Structural change by high-energy ion irradiation and post-annealing in EuBa2Cu3Oy

Structure of columnar defects is studied by the measurement of change in c-axis lattice parameter as a function of fluence in thin films of EuBa2Cu3Oy irradiated with 200 MeV Au13+ ions at RT. Change rate of the c-axis lattice parameter for the sample with O content of y=7 is same as that for the sample with O content of y=6. The c-axis lattice parameter is recovered by post-annealing at 550 C. The above results indicate that the softly damaged region, which surrounds the well-known amorphized region, is vanished by the thermal annealing. It also shows that the softly damaged region is mainly composed of the defects of the elements other than the chain-site O. 13 refs.