Ion irradiation-induced phase transformations in bixbyite-fluorite related oxides: The role of dislocation loop nucleation

The ion irradiation induced phase transformations of bixbyite-fluorite related oxides have been studied with thin films of Y2O3 grown on Si and SrTiO3 by an ion beam sputtering technique which allows to control the microstructure and stresses within the film. Y2O3 thin films are ion-irradiated with an xenon beam in an energy range 60–380keV at a fluence of 4.4×1015 Xe/cm2 at 80K. Depending on the energy of the xenon beam two different structural phase transformations are observed: cubic to nanocrystalline/amorphous and cubic to monoclinic phase transformations. The phase transformation are analysed in terms of structural extended defect nucleation like prismatic dislocation loops due to the oxygen network behaviour under ion irradiation.