Swift heavy ion irradiation-induced phase transformation in oxide materials

Abstract

The present study briefly reviews the effect of ion irradiation in inducing structural transformation in oxide materials. The effect of ion irradiation on simple systems such as Y₂O₃, CuO, ZrO₂, HfO₂ and TiO₂ and a few members of the high T _c cuprate superconductor family are examined. Some of the phase transformations induced are shown to be uniquely possible by swift heavy ion (SHI) irradiation and cannot be achieved by thermal annealing. In nanoparticle thin films of TiO₂, irradiation is shown to completely transform the anatase phase to a rutile phase, whereas thermal annealing even at 1273 K could not lead to complete conversion. The thermal spike model of ion–matter interaction is shown to explain ion irradiation-induced phase transformation in most of the oxide materials. In a more complex system like the high T _c superconductor YBa₂Cu₃O₇, secondary electrons radially emerging from the path of SHI are shown to induce selective disorder in the CuO basal planes without affecting the net oxygen content. This unique feature of SHI is not achievable by any other techniques.

Keywords:

• ion irradiation
• phase transformation
• oxides