Recent researches of the copper centres in potassium tantalate single crystals

Electron paramagnetic resonance (EPR) of single. Cu(2+) ions and exchange-coupled Cu(2+)-Cu(2+) pairs in KTaO(3), KTaO(3):Li:Cu and KTaO(3):Li:Nb crystals has been analyzed in the temperature range of 300 - 1000 K. The temperature stability of the paired centers was found to be similar to that of single Cu(2+) ions. The influence of oxygen vacancies on the Cu(2+) EPR spectra was studied.