Latent Tracks in Ion-Irradiated LiTaO3 Crystals: Damage Morphology Characterization and Thermal Spike Analysis

Xinqing Han,Eva Zarkadoula,Miguel L Crespillo,Qing Huang,Yong Liu,Xuelin Wang,Peng Liu

doi:10.3390/cryst10100877

Abstract

Systematic research on the response of crystal materials to the deposition of irradiation energy to electrons and atomic nuclei has attracted considerable attention since it is fundamental to understanding the behavior of various materials in natural and manmade radiation environments. This work examines and compares track formation in LiTaO3 induced by separate and combined effects of electronic excitation and nuclear collision. Under 0.71–6.17 MeV/u ion irradiation with electronic energy loss ranging from 6.0 to 13.8 keV/nm, the track damage morphologies evolve from discontinuous to continuous cylindrical zone. Based on the irradiation energy deposited via electronic energy loss, the subsequently induced energy exchange and temperature evolution processes in electron and lattice subsystems are calculated through the inelastic thermal spike model, demonstrating the formation of track damage and relevant thresholds of lattice energy and temperature. Combined with a disorder accumulation model, the damage accumulation in LiTaO3 produced by nuclear energy loss is also experimentally determined. The damage characterizations and inelastic thermal spike calculations further demonstrate that compared to damage-free LiTaO3, nuclear-collision-damaged LiTaO3 presents a more intense thermal spike response to electronic energy loss owing to the decrease in thermal conductivity and increase in electron–phonon coupling, which further enhance track damage.

Highlights

Recent research has demonstrated that perovskite-type LiTaO3 crystals, as representative functional oxides, have extensive potential applications in various radiation environments, such as tritium breeding in fusion reactors [1,2], nuclear waste immobilization [3], and radiation detection [4]
stopping and range of ions in matter (SRIM) 2013 simulation code is primarily used to determine the profile of electronic energy loss as a function of ion penetration path, and could not provide the radial distribution of deposited irradiation energy via electronic energy loss process at a certain penetration depth, which is essential for the inelastic thermal spike (iTS) calculations so as to obtain the radial evolutions of electron and lattice temperatures and further describe the lattice melting behavior
During the ion slowing process, the interaction cross section between the irradiating ion and target electrons and the subsequently induced electron cascade in the target directly depend on the ion velocity, which would further determine the radial distribution of the energy deposited in the electron subsystem via the electronic energy loss process

Summary

Introduction

Recent research has demonstrated that perovskite-type LiTaO3 crystals, as representative functional oxides, have extensive potential applications in various radiation environments, such as tritium breeding in fusion reactors [1,2], nuclear waste immobilization [3], and radiation detection [4]. In the research field of ion–solid interactions and irradiation effects, systematic study of the response of crystal materials to the deposition of irradiation energy to electrons and atomic nuclei has always attracted considerable attention. Through appropriate choices of irradiating ion energies, velocities, and energy loss intensities, the role of irradiation energy deposited to electron and lattice subsystems and the induced lattice-defect production and structure evolution in LiTaO3 crystals are studied comprehensively. By combining the microstructure characterizations with inelastic thermal spike model calculations, the formation of latent tracks with different damage morphologies under the action of electronic energy loss and the corresponding threshold conditions are analyzed. The coupled effect between the electronic excitation and nuclear collision on the thermal spike response and the induced enhanced track damage behavior are further experimentally characterized and theoretically demonstrated

Methods

Results

Conclusion