Luminescence spectroscopy of iron-doped KTaO3 crystals

KTaO3 crystals slightly doped with iron were investigated by luminescence s pectroscopy. A zero-phonon line was found in the low-temperature emission a t 14 569 cm(-1) under excitation in the spectral region 15 000-24 000 cm(-1 ). The results suggest that this luminescence originates from Fe3+ (d(5)) i ons substituted for K+. The excitation and emission are assigned to the (6) A(1)(S) --> T-4(1)(G), T-2(2)(I), T-4(2)(G), and T-4(1)(G) --> (6)A(1)(S) t ransitions, respectively. The following crystal field parameters of Fe3+ in KTaO3 were found: Dq = 1230 cm(-1), B = 690 cm(-1), and C = 3452 cm(-1).