Point defects induced in yttria-stabilized zirconia by electron and swift heavy ion irradiations
Résumé
We present an extensive study of point-defect creation in yttria-stabilized zirconia (ZrO2:Y) exposed to 2.5 MeV electrons and various heavy ions (from C to U) covering an energy range from 100 MeV to several GeV. A synthesis of results from UV–visible optical absorption spectroscopy and electron paramagnetic resonance spectroscopy is provided with special emphasis on the respective roles of elastic collisions and electronic excitations. The colour centre production and recovery are the main focus in this survey. It is concluded that F+-type centres (involving singly ionized oxygen vacancies) are produced by elastic-collision processes. The large threshold displacement energy and defect volume hint that these colour centres might actually be small paramagnetic oxygen vacancy clusters, most probably divacancies (i.e. F+2 centres). Such a picture is consistent with the (100) axial symmetry, inhomogeneous broadening of the optical absorption band, lack of hyperfine splitting, and weak spin–lattice coupling found for this defect.