Energy beam irradiation of high-T_csuperconductors Y₁Ba₂Cu₃O_7-yand Ho₁Ba₂Cu₃O_7-y

We have investigated energy beam irradiation of high-T_c superconductors which were treated in various ways. It is found for the first time that infrared-light irradiation and cw-laser irradiation for short periods are useful to get an orthorhombic phase with T_c of about 90 K at local regions from a tetragonal phase or a quenched amorphous-like phase, including mixed tetragonal and orthorhombic phases. It is likely that an amorphous phase produced by ion implantation of 400 keV O⁺ up to a dose of 1×10¹⁷/cm² is transformed to the superconducting orthorhombic phase by thermal annealing at 900 and 950°C.