Substituting Sites of Rare Earth Ions in BaTiO3

The electron spin resonance experiment has been performed in reduced ceramic samples of BaTiO 3 containing La 3+ ions. A characteristic F-center signal was observed for the Ba/Ti ration of 1.02. This observation of F-center signal indicates strongly that some of doped La 3+ ions substitute Ti 4+ ions and act as acceptors. The effect of some monovalent and trivalent ions on the substituting sites of Gd 3+ ions has been also investigated. It was found that for a low concentration of monovalent ions they formed “pairs” with Gd 3+ ions at Ba 2+ sites.