Hyperfine interactions and diffusion of Cd in TiO (rutile)

Zyabkin D V, Schell J, Gaertner D, Dang T T, Gonçalves J N, Marschick G, Schaaf P

Abstract

In the current work, we present an investigation of the electronic and defect structure in (TiO 2 ) rutile monocrystals by virtue of time differen-tial perturbed angular γ-γ correlation spectroscopy. Studies were performed using 111m Cd, implanted at ISOLDE/CERN complemented withdiffusion studies and density functional theory calculations. Hyperfine field parameters have been probed as a function of temperature between298 K and 873 K. The results demonstrate that 111m Cd/Cd implanted rutile has two local environments. The first environment is characterizedwith parameters attributed to Cd localized at the cationic site which goes relatively along with a specific case where a charged supercell Cd:Ti(2e
) is in the scope. The origin of the second fraction could be rising from the subsurface regions where according to a tracer diffusion studythe major part of implant is bounded featuring different diffusion mechanisms. Performed ab initio calculations suggest that the disruptivesurface environment could contain apical or equatorial vacancies near the probe, inducing high electric field gradients for the second fraction.Current results seem to differ from those obtained before with different methods of probing (Ag/Cd and In/Cd).