Photoluminescence and decay profiles of undoped and Fe3+, Eu3+-doped PLZT ceramics at low temperatures down to 10 K

Luminescence, time-resolved luminescence, excitation spectra and lifetimes of nominally pure and Eu, Fe-doped PLZT ceramics with perovskite A (Pb, La) B (Zr, Ti) O-3 structure are investigated as a function of temperatures down to 10 K in order to elucidate luminescence centers in hot-/cold-pressed PLZT (9/65/35) and cold-pressed PLZT (8/70/30). At 10 K, the luminescence band of PLZT is considered to consist of two bands centered at 18 100 cm(-1) (center 1) and 15 600 cm(-1) (center 2) with lifetimes of about tau(1) = 1 ms and tau(2) = 60 mu s, respectively. Comparing luminescence, lifetimes and excitation spectral properties of various PLZT samples, center 1 can be assigned to octahedral [Ti(IV)O-6] structures which are present in the cold-pressed, polycrystalline samples. Center 2 is identified as being due to ore-coordinated octahedral Fe3+ ions associated with oxygen and lead-deficient octahedral [BO6 - delta] (B = Ti4+, Zr4+) complexes in defect domains in the hot-pressed ceramics. Blue shift to 19 500 cm(-1) and an abrupt shortening of lifetimes to 0.1 ms were observed at around 160 K due to the phase transition. (C) 2000 Elsevier Science S.A. All rights reserved.