Mössbauer-effect study of Co57 and Fe57 impurities in ferroelectric LiNbO3
Abstract
The Mössbauer effect observed with LiNbO3:Co57 (source) and LiNbO3:Fe57 (absorber) crystals showed the existence of high-spin Fe2+ and Fe3+ valence states. The Fe2+/Fe3+ ratio could be changed by reducing or oxidizing heat treatment. Fe3+ in sources and absorbers shows Mössbauer spectra which are typical for slow electronic relaxation between the crystal field states of the 6S5/2 state ion. For both Fe3+ and Fe2+, the principal axis of the electric field gradient is found to be parallel to the crystallographic c axis. For ferric iron Vzz is positive, while Vzz is negative and strongly temperature dependent for ferrous iron. The impurity site substitution and charge compensation mechanism are discussed.
- Publication:
-
Journal of Applied Physics
- Pub Date:
- September 1975
- DOI:
- 10.1063/1.322139
- Bibcode:
- 1975JAP....46.3914K
- Keywords:
-
- 71.55.Ht;
- 76.80.+y;
- 71.70.Ch;
- Other nonmetals;
- Mossbauer effect;
- other gamma-ray spectroscopy;
- Crystal and ligand fields