Doping of sapphire single crystals with In-111 and Cd-111m detected by perturbed angular correlation

The electric hyperfine interaction of ion beam implanted In-111 and Cd-111m probe atoms in sapphire (Al2O3) single crystals has been investigated usin g perturbed angular correlation spectroscopy. For both probe atoms the same distinctive electric field gradient was found, indicating that nearly all the implanted probe atoms form a stable substitutional configuration in the temperature range between 77 K and 873 K on the aluminum sublattice. A com parative study between In-111 and Cd-111m-measurements points to a dynamic interaction initiated by the electron-capture of In-111(EC)Cd-111 similar t o In2O3 and La2O3. Size and orientation of the EFG are discussed in compari son to experimental results in Cr2O3 single crystals.