Hyperfine interactions and diffusion of Cd in TiO2 (rutile)

Abstract

In the current work, we present an investigation of the electronic and defect structure in (TiO2) rutile monocrystals by virtue of time differential perturbed angular γ-γ correlation spectroscopy. Studies were performed using 111mCd, implanted at ISOLDE/CERN complemented with diffusion studies and density functional theory calculations. Hyperfine field parameters have been probed as a function of temperature between 298 K and 873 K. The results demonstrate that 111mCd/Cd implanted rutile has two local environments. The first environment is characterized with 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 study the major part of implant is bounded featuring different diffusion mechanisms. Performed ab initio calculations suggest that the disruptive surface 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).