Abstrakt
Temperature dependence of nuclear magnetic resonance (NMR) spectra of 47Ti and 49Ti in polycrystalline ilmenite FeTiO3 was measured in the range from 5 to 300 K under an external magnetic field of 9.401 T. NMR spectra collected between 300 and 77 K exhibit a resolved quadrupole splitting.
The electric field gradient (EFG) tensor was evaluated for Ti nuclei and the ratio of 47Ti and 49Ti nuclear quadrupole moments was refined during the fitting procedure. Below 77 K, the fine structure of quadrupole splitting disappears due to the enormous increase of anisotropy.
As a counterpart, ab initio calculations were performed using full potential augmented plane waves + local orbitals. The calculated EFG tensors for Ti and Fe were compared to the experimental ones evaluated from NMR and the Mossbauer spectroscopy experiments.