PARAMAGNETIC DEFECTS IN BATIO3 AND THEIR ROLE IN LIGHT-INDUCED CHARGE TRANSPORT .1. ESR STUDIES

An overview on paramagnetic defects in BaTiO3 single crystals, used in photorefractive applications, is given. New results concerning cation defects include the investigation of double quantum transitions in isolated Fe3+, identification of the parameters of Fe4+-V0, analysis of Co2+, the report of Co4+-V0, Jahn-Teller-induced spin-lattice relaxation effects of Pt3+, identification of Rh2+, Rh4+, Ir4+ and Pt5+. In the field of anion defects O- trapped hole centres associated with unknown acceptors and with Al3+ are reported. The role of the identified defects in light-induced charge transport processes is discussed.