摘要
Polycrystalline pyrochlore Lu2Ti2O7 pellets are irradiated with 600-keV Kr^3+ions up to a fluence of 1.45 ×10^16Kr^3+/cm^2. Irradiation induced structural modifications are examined by using grazing incidence x-ray diffraction(GIXRD) and cross-sectional transmission electron microscopy(TEM). The GIXRD reveals that amorphous fraction increases with the increase of fluences up to 2 × 10^15Kr^3+/cm^2, and the results are explained with a direct-impact model.However, when the irradiation fluence is higher than 2 × 10^15Kr^3+/cm^2, the amorphous fraction reaches a saturation of-80%. Further TEM observations imply that nano-crystal is formed with a diameter of -10 nm within the irradiation layer at a fluence of 4 × 10^15Kr^3+/cm^2. No full amorphization is achieved even at the highest fluence of 1.45 × 10^16Kr^3+/cm^2(-36 displacement per atom). The high irradiation resistance of pyrochlore Lu2Ti2O7 at higher fluence is explained on the basis of enhanced radiation tolerance of nano-crystal structure.
Polycrystalline pyrochlore Lu2Ti2O7 pellets are irradiated with 600-keV Kr^3+ions up to a fluence of 1.45 ×10^16Kr^3+/cm^2. Irradiation induced structural modifications are examined by using grazing incidence x-ray diffraction(GIXRD) and cross-sectional transmission electron microscopy(TEM). The GIXRD reveals that amorphous fraction increases with the increase of fluences up to 2 × 10^15Kr^3+/cm^2, and the results are explained with a direct-impact model.However, when the irradiation fluence is higher than 2 × 10^15Kr^3+/cm^2, the amorphous fraction reaches a saturation of-80%. Further TEM observations imply that nano-crystal is formed with a diameter of -10 nm within the irradiation layer at a fluence of 4 × 10^15Kr^3+/cm^2. No full amorphization is achieved even at the highest fluence of 1.45 × 10^16Kr^3+/cm^2(-36 displacement per atom). The high irradiation resistance of pyrochlore Lu2Ti2O7 at higher fluence is explained on the basis of enhanced radiation tolerance of nano-crystal structure.
基金
Project sponsored by the National Natural Science Foundation of China(Grant No.11205128)
the Fundamental Research Funds for the Central Universities
China(Grant No.2012121034)