ESR study of BaTiO3 ceramics doped by Y and Ca

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.