Neodymium sites in calcium lanthanide hexaaluminates, potential laser materials

Journal Article · Thu Dec 01 00:00:00 EST 1988 · J. Solid State Chem.; (United States)

DOI:https://doi.org/10.1016/0022-4596(88)90242-3· OSTI ID:6188763

Gbehi, T; Thery, J; Vivien, D; Collongues, R; Dhalenne, G; Revcolevschi, A

The calcium (CaAl/sub 12/O/sub 19/) and lanthanide (LnAl/sub 11/O/sub 18/ and LnMgAl/sub 11/O/sub 19/ with Ln = La/sub 1-sigma/Nd/sub ..cap alpha../) hexaaluminates form a full series of solid solutions labeled CLnA. Pure phases are prepared by solid state reactions at high temperatures (greater than or equal to 1550/degrees/C); however, single crystals are obtained only when CLnA contains also Mg/sup 2 +/ ions. These crystals can be grown by the melting zone techniques use an arc image furnace. The structure of CLnA is of the magnetoplumbite-type, with unit cell parameters intermediate between those of the two parent compounds. When calcium is replaced by barium, there is no solid solution and a compound (BLnA) with different structure is formed. This difference seems to be related to the structural difference between the two alkaline earth hexaaluminates CaAl/sub 12/O/sub 19/ and BaAl/sub 12/O/sub 19/. Optical absorption, fluorescence, and ESR spectra of Nd/sup 3 +/ in CLnA single crystals have been investigated for various starting compositions Ca/sub 1-x/(La/sub 1-..cap alpha../Nd/sub ..cap alpha../)/sub x/Mg/sub x/Al/sub 12-x/O/sub 19/ and compared with those of lanthanum-neodymium hexaaluminate (LNA), which is promising laster material. While in LNA, Nd/sup 3 +/ ions are distributed among three almost equally populated sites; in CLnA only two of these sites have been shown to be occupied. Furthermore, one of the two sites, with nearly axial symmetry, is much more populated than the other one. The higher the calcium content of CLnA, the higher the Nd/sup 3 +/ occupancy ratio in this axial site. The fluorescence spectra of LNA and CLnA are very similar. All these results suggest that as a laser material, CLnA could present some interesting particularities compared to LNA.

• Research Organization: Laboratoire de Chimie Appliquee de l'Etat Solide, Paris (France)
• OSTI ID: 6188763
• Journal Information: J. Solid State Chem.; (United States), Vol. 77:2
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
42 ENGINEERING
LANTHANUM COMPOUNDS
PHASE STUDIES
LASER MATERIALS
NEODYMIUM COMPOUNDS
ALUMINIUM OXIDES
CALCIUM COMPOUNDS
ELECTRON SPIN RESONANCE
EXPERIMENTAL DATA
FLUORESCENCE
LASERS
SOLID SOLUTIONS
ALKALINE EARTH METAL COMPOUNDS
ALUMINIUM COMPOUNDS
CHALCOGENIDES
DATA
DISPERSIONS
INFORMATION
LUMINESCENCE
MAGNETIC RESONANCE
MATERIALS
MIXTURES
NUMERICAL DATA
OXIDES
OXYGEN COMPOUNDS
RARE EARTH COMPOUNDS
RESONANCE
SOLUTIONS
400201* - Chemical & Physicochemical Properties
420300 - Engineering- Lasers- (-1989)