STRUCTURAL AND ELECTRONIC MODIFICATIONS IN ION-BEAM TREATED YTTRIUM-OXIDE

Disorder induced by ion beam treatments (irradiation with energetic Au ions or Zr implantation) in the Y2O3 ceramic has been studied. By combining several experimental techniques, we obtained information on electronic distributions and on atomic rearrangements around each species of the matrix. Three types of defects have been investigated. They are the intrinsic defects: on the oxygen and Y sublattices, and an extrinsic defect: the implanted impurity, here Zr, a cation greedy of oxygen. No amorphisation was reached under the experimental beam conditions used here. The whole matrix remained well crystallized, despite the fact that the final disorder around the impurity, located on a substitutional site, was rather large. Oxygen desorption occurred on the ion beam treated depth. We found that (i) oxygen vacancies appeared to be ordered and (ii) there was a competition between energy deposition via atomic collisions which induced 0 desorption and chemical effects due to Zr implantation which retained O.