57Fe Mössbauer spectroscopy was performed on two types of Fe oxide nanoparticles supported on a typical ferroelectric, BaTiO3. It was found that the valence state of FeO nanoparticles changed to a mixed 2+/3+ state at high temperature where BaTiO3 shows paraelectric behaviour. We attribute this phenomenon to the fluctuation of electric dipoles which realizes carrier injection into the Fe oxides. This is the first report which discusses a dynamical valence state of transition metal oxides supported on ferroelectrics.
ASJC Scopus subject areas
- Condensed Matter Physics
- Nuclear and High Energy Physics
- Atomic and Molecular Physics, and Optics
- Physical and Theoretical Chemistry