Sensitivity of Anatase and Rutile Phases of TiO 2 to ion irradiation: Examination of the applicability of Coulomb Explosion and Thermal Spike Models
Résumé
Sensitivity of the anatase and rutile phases of titanium dioxide to Swift Heavy Ion (SHI) irradiation was
experimentally probed and compared with the predictions of the Coulomb explosion, analytical and
inelastic thermal spike models of ion-matter interaction. Conforming to the predictions of all these
models, our study indicated higher sensitivity of anatase to these ions than the rutile phase. A detailed
examination however revealed that Coulomb explosion model cannot explain either the nature of
variation of the interaction cross section of SHI with the energy deposited by these ions, Se to the target
electrons, or the relative values of the threshold electronic energy loss, Seth of anatase and rutile. The
analytical thermal spike (a-TS) model, using the available physicochemical data for this oxide, predicted
that tracks cannot form either in anatase or in rutile by 297 MeV and 511 MeV Ni ions, while inelastic
thermal spike (i-TS) model predicted formation of ion tracks by 297 MeV Ni ions and their absence
with 511 MeV Ni ions in both anatase and rutile. Our observation agreed with the predictions of i-TS
model albeit with a difference in the radius of the tracks. In addition, we observed halo of defect ridden
crystalline region of much larger radius around the ion track. Interestingly, the radius of the halo scales
with the velocity of the ions, which is opposite to the conventionally observed velocity effect.
Origine | Fichiers éditeurs autorisés sur une archive ouverte |
---|
Loading...