Eur. Phys. J. B 34, 395-398 (2003)
https://doi.org/10.1140/epjb/e2003-00236-x

Evidence of an ion-beam induced crystalline-to-crystalline phase transformation in hafnia

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

Corresponding author: ^a benyagoub@ganil.fr

Received: 4 February 2003
Revised: 6 June 2003
Published online: 9 September 2003

Abstract

Samples of monoclinic hafnia were irradiated with increasing fluences of 800 and 300 MeV Kr ions giving rise to a slowing down essentially caused by high electronic excitations. Their structural evolution was monitored in situ by the X-ray diffraction technique. The results indicate, for the first time to our knowledge, the occurrence in monoclinic hafnia of an ion-beam induced crystalline-to-crystalline phase transition. The new formed phase is very likely tetragonal and appears with an effective threshold in the deposited electronic energy loss which is around 20 keV nm^-1. In addition, the evolution of the amount of the produced phase with the ion fluence exhibits a sigmoidal shape suggesting a mechanism for phase transformation which needs two ion impacts. Some features of this phase transition are compared with those obtained in the case of zirconia, a well-known isomorphic material with hafnia.