EXAFS Study of Radiation-Induced Defects in Molybdenum and Tantalum Metals
Andrianov V.A. Bedelbekova K.A. Erzinkyan A.L. Trigub A.L.
August 2022Pleiades journals
Journal of Surface Investigation
2022#16Issue 4441 - 447 pp.
Abstract: Radiation defects arising from the high-dose implantation of 57Fe+ ions into matrices of refractory Mo and Ta metals are studied by Extended X-ray Absorption Fine Structure (EXAFS) spectroscopy in the region of the Fe K-edge Fe. The concentration of Fe atoms, which is calculated using the SRIM program, is 2.5 at % at a depth of ≈300 nm. The concentration of radiation-induced defects exceeds 100 dpa. The positions of Fe atoms are determined in the samples after implantation and additional annealing at 700°C. In Mo, Fe atoms are predominantly located in substitution positions in a body-centered cubic (bcc) crystal lattice. An analysis of the EXAFS spectra shows that, on average, 1.4 atomic vacancies are in the first coordination sphere of Fe, which corresponds to a vacancy concentration of about 24 at %. In the Ta matrix, Fe atoms are located in a more complex manner. To analyze the data, model EXAFS spectra are calculated for typical atomic configurations of Fe atoms in a Ta matrix, which form as a result of irradiation. Relaxation of the crystal environment of Fe atoms is taken into account by the density-functional-theory method. Comparison of the experimental spectra with the calculated ones shows that Fe atoms are located in several positions in Ta, including interstitial and substitution positions. Annealing leads to a change in the coordination and partial segregation of Fe atoms. The EXAFS data are consistent with previously published Mössbauer-spectroscopy data. It is demonstrated that the EXAFS method makes it possible to more accurately determine the configurations of defects arising from irradiation.
electron density-functional theory , EXAFS spectroscopy , interstitial positions , Mo, Ta, Fe, implantation , radiation-induced defects , SRIM , substitution positions , vacancies
Text of the article Перейти на текст статьи
Lomonosov Moscow State University, Institute of Nuclear Physics, Moscow, 119991, Russian Federation
Institute of Nuclear Physics of the Republic of Kazakhstan, Almaty, 050032, Kazakhstan
National Research Center “Kurchatov Institute”, Moscow, 123182, Russian Federation
Lomonosov Moscow State University
Institute of Nuclear Physics of the Republic of Kazakhstan
National Research Center “Kurchatov Institute”
10 лет помогаем публиковать статьи Международный издатель
Книга Публикация научной статьи Волощук 2026 Book Publication of a scientific article 2026