Ion implantation in high-T_c superconductors

Abstract

We describe effects that occur when high-Tc oxide superconductors are ion implanted or irradiated. Most of the information has come from studies done with MeV ions and thin films of YBa2Cu3O7, and many of the changes are due to radiation damage. Small ion doses introduce defects which are mobile, and anneal at room temperature. At high dose the materials are no longer superconductors, and the effects seen with increasing ion fluence are a reduction in the normal-state conductivity, which falls exponentially with dose, and a metal to semiconductor transition. These can be viewed as consequences of increasing localization of the charge carriers. At still higher doses a crystalline-to-amorphous transition occurs. Some progress in ion-implantation processing of superconducting thin films has been made, in particular in patterning the films with high implant doses. © 1989.