Electron paramagnetic resonance results for pure single crystals doped with Co2+ ions, as well as results for KTaO3:Cu single crystals, were presented. Divalent impurity ions replaced Ta5+ in the octahedral positions of the KTO3 crystal, and O vacancies were required in order to compensate the extra charge of Ta5+. The Cu2+ ions associated with O vacancies formed only axial centres (included exchange coupled pair centre); the symmetry axes being directed along cubic directions. A new axial centre of Co2+ in KTaO3:Co crystals was studied.

Divalent Impurity Ion Defects in Potassium Tantalate - EPR Investigations. A.G.Badalyan, V.A.Trepakov, C.B.Azzoni, P.Galinetto, M.C.Mozzati, L.Jastrabik, J.Rosa, S.E.Kapphan, M.Hrabovsky: Physica Status Solidi C, 2005, 2[1], 141-4