Atomistic simulation of amorphization thermokinetics in lanthanum pyrozirconate

The kinetics of amorphization in La2Zr2O7 pyrochlore is investigated using molecular dynamics simulations. Irradiation damage is simulated by continuous accumulation of cation Frenkel pairs at various temperatures. As observed experimentally, La2Zr2O7 first transitions to the fluorite structure, independent of the temperature, and amorphization occurs at low temperatures. A model fit of the simulated dose-temperature curve reproduces experimental results in the literature, with a low temperature amorphization dose D-0=1.1 displacement per cation and an activation energy E-act=0.036 eV. Present simulations indicate that point defect recombination can control the temperature dependence of amorphization driven by point defect accumulation. (c) 2006 American Institute of Physics.