Study of the Structural Characteristics of 3d Metals Cr, Mn, Fe, Co, Ni, and Cu Implanted in ZnO and TiO2—Experiment and Theory

Herein we systematically study a range of dopants (Cr, Fe, Ni, Cu, and an MnCo alloy) in ZnO and TiO2 using several X-ray spectroscopic techniques. We identify the dopant’s local environment and interaction with the host lattice by employing crystal field multiplet calculations and hence clarify their potential applicability for spintronic technologies. Our density functional theory (DFT) calculations predict a decreasing probability of direct cation (Zn/Ti) substitution by dopant atoms as atomic number increases, as well as a much greater likelihood of metallic clustering in TiO2. Our spectroscopic measurements confirm that in all cases, except Mn, metallic clusters of dopant atoms form in the TiO2 crystal lattice, thus making it unfit for spintronic capabilities. On the other hand, in ZnO, the dopants substitute directly into zinc sites, which is promising for spintronic technologies.