ESR AND OPTICAL STUDIES OF NEODYMIUM-EXCHANGED SODIUM BETA-ALUMINOGALLATE SINGLE-CRYSTALS

Optical and ESR studies of Nd3+-exchanged sodium aluminogallate single crystals with beta-alumina structure indicate that Nd3+ is located in only one site having an axial symmetry. This site could be identified with the BR position of the conduction planes. The oscillator strength of the Nd3+ hypersensitive transition of the absorption spectrum is equal to 37 x 10(-6). This is anomalously high compared to other Nd3+-activated materials. The Nd3+ excited-state lifetime, 454-mu-s for neodymium concentration close to 10(21) ions per cm3, is also very high indicating that the fluorescence self-quenching is weak in this material.