Dramatic change of the kinetics of the phase transition induced in pure zirconia by swift heavy-ion irradiation

Centre Interdisciplinaire de Recherche Ions Lasers (CIRIL), CEA-CNRS-ISMRA BP 5133, F-14070 Caen Cedex 5, France

Received: 22 April 2002
Accepted: 3 September 2002

Abstract

It is generally admitted that the irradiation of crystalline materials with high-energy heavy ions often leads to the formation of highly defective or amorphous tracks. In the latter case, the amorphization process follows a single-ion-impact mechanism. However, recent results demonstrate that in certain circumstances crystalline-to-crystalline phase transitions can also occur. This is well illustrated with the case of pure zirconia which can undergo a transition from the monoclinic to the tetragonal phase with a kinetics characterized by a sigmoidal shape. The present study provides new evidence that this transformation is driven by a double-ion-impact mechanism. Another important finding is that the steepness of the sigmoid depends drastically on the amount of the electronic-energy loss: a small change in this parameter leads to a catastrophic modification of the kinetics of the phase transition.