OPTICALLY INDUCED CHARGE-TRANSFER PATHS BETWEEN DEFECTS IN BATIO3 CONTAINING RHODIUM

An optical method is presented which allows to identify at room temper ature the photoinduced charge transfers between different defects in p hotorefractive crystals. The analysis is based on the labelling of the optical spectra with the corresponding microscopic defect models, obt ained from simultaneously recording light induced ESR and optical abso rption changes at low temperatures. The investigation of as-grown BaTi O3 crystals containing Rh, using this method, shows that illumination with light of energies between 1.2 eV and 2.5 eV transfers holes from Rh4+ to Fe3+. At E > 2.5 eV holes are photoionized from Fe4+ to Rh3+ a nd to an unidentified shallower hole trap.