ESR study of BaTiO₃ ceramics doped by Y and Ca

Abstract

Electron spin resonance (ESR) investigation of BaTiO₃ ceramics doped by Y and Ca has been presented. It is shown that the most intensive resonance line belongs to the Ti³⁺-Y³⁺ paramagnetic complex. The essential decrease of Ti³⁺-Y³⁺ ESR spectra intensity in comparison with that in samples without Ca is revealed. This gives evidence that Ca ions decrease the number of Y³⁺ ions substituted for Ba ions and so the number of the Ti³⁺-Y³⁺ centers decreases. It was shown that grain size of BaTiO₃ ceramics became smaller under Ca doping though the temperature region of the effect of positive temperature coefficient of resistivity remain practically unchanged.

Key Words:

• ceramics
• ESR
• paramagnetic center
• PTCR effect