Kinetics of the crystalline to crystalline phase transformation induced in pure zirconia by swift heavy ion irradiation

Abstract

It is generally admitted that the irradiation of crystalline oxides with high energy heavy ions, where the slowing down is mainly due to electronic excitations or ionizations, 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 the case of pure zirconia which transforms from the monoclinic to the tetragonal phase when the deposited electronic energy loss exceeds an effective threshold near 13 keV nm −1. Moreover, recent experiments exploring a wide range of the deposited electronic energy loss demonstrate that the kinetics of phase transformation is always sigmoidal and is consistently characterized by a double ion impacts mechanism. Therefore, it seems that this process is a constant feature of this ion-beam induced crystalline to crystalline phase transition. The origin of this behaviour will be discussed and confronted with the existing models.