Charged particle damage studies of YBa2Cu3O7

In the work of previous authors, thin films of YBa2Cu3O7 compound were irradiated by He2+ ions, with energies of 3.6 and 6.7 MeV, at room temperature. They observed a strong dependence of Tc on the fluence F, with Tc < 4.2 K for > 2 x 1016 ion cm-2. They did not observe any transition from orthorhombic to tetragonal phase during irradiation, but unit cell parameters were increased by some tenths of a per cent. In that work, it was supposed that irradiation damage at copper and oxygen sublattices has the main influence on Tc reduction. In order to obtain complementary results, and to verify the hypothesis, we began an irradiation damage study with 28 MeV α-particles on a YBaCuO compound of nominal composition YBa2Cu3O7. (author)