Lattice defects in rhodium and iridium trapped at¹¹¹In probe atoms

Abstract

The interaction of intrinsic lattice defects with¹¹¹In probe atoms in the fcc metals rhodium and iridium has been studied between 293 and 1,400 K by means of the time differential perturbed angular correlation method. The lattice defects were produced either by the implantation of the probe atoms or by postirradiation with protons. In rhodium a unique defect-probe atom configuration leading to a quadrupole interaction frequencyv _Q1=100(2)MHz and η=0 has been observed. The symmetry axis of the corresponding electric field gradient points into the 〈110〉 direction of the fcc lattice. The defect was interpreted as a monovacancy trapped at the probe atom in the 〈110〉 nearest neighbour position. In iridium two defects characterized byv _Q1=118(2)MHz, η=0 andv _Q2=228(2)MHz, η=0 have been observed. The symmetry axes of the corresponding electric field gradients point into the 〈110〉 and 〈111〉 directions and the defects were interpreted as a monovacancy in a nearest neighbour position and a relaxed divacancy, respectively.