Vacancy trapping at¹¹¹In in tungsten

Abstract

TDPAC measurements were carried out in tungsten foils and single crystals using implanted¹¹¹In as a probe nucleus. After damaging the bcc tungsten lattice by heavy ion implantation, electron- and proton-irradiation the trapping of three different defects in the temperature range 293–1,000 K was observed. They were characterized by quadrupole interaction frequencies of v ¹ _Q = 142(2) MHz, v ² _Q = 181(5) MHz and v ³ _Q = 263(5) MHz. The largest fraction of In nuclei experiencing electric field gradients corresponding to v ¹ _Q and v ² _Q was reached at app. 630 K whereas for v ³ _Q this maximum appeared at app. 850 K. The defect configurations producing the different electric field gradients could be identified as a monovacancy trapped in a nearest neighbour 〈111〉 position (v ¹ _Q ), a double vacancy consisting of two adjacent vacancies in the nearest neighbour shell of the probe atom (v ² _Q ) and possibly a larger cluster (v ³ _Q ).