A Comparative Study of Electron Radiation Responses of PuZrO and LaZrO: An Molecular Dynamics Study.

In this study, the response of PuZrO and LaZrO to electronic radiation is simulated, employing an molecular dynamics method. It is shown that PuZrO undergoes a crystalline-to-amorphous structural transition with 0.3% electronic excitation, while for LaZrO, the structural amorphization occurs with 1.2% electronic excitation. During the microstructural evolution, the anion disorder further drives cation disorder and eventually results in the structural amorphization of PuZrO and LaZrO. The difference in responses to electron radiation between PuZrO and LaZrO mainly results from the strong correlation effects between Pu 5 electrons and the smaller band gap of PuZrO. These results suggest that PuZrO is less resistant to amorphization under local ionization rates that produce a low level of electronic excitation, since the level of the concentration of excited electrons is relatively low in PuZrO. The presented results will advance the understanding of the radiation damage effects of zirconate pyrochlores.