Atomistic modeling and experimental studies of radiation damage in monazite-type LaPO_4 ceramics

摘要

We simulated the threshold displacement energies (E_d), the related displacement and defect formation probabilities, and the energy barriers in LaPO_4 monazite-type ceramics. The obtained E_d values for La, P, 0 primary knock-on atoms (PKA) are 56 eV, 75 eV and 8 eV, respectively. We found that these energies can be correlated with the energy barriers that separate the defect from the initial states. The E_d values are about twice the values of energy barriers, which is explained through an efficient dissipation of the PKA kinetic energy in the considered system. The computed E_d were used in simulations of the extent of radiation damage in La_(0.2)Gd_(0.8)PO_4 solid solution, investigated experimentally. We found that this lanthanide phosphate fully amorphises in the ion beam experiments for fluences higher than ～10~(13) ions/cm~2.