Growth, structural and optical characterizations of LiLa{sub (1-x)}Eu{sub x}(WO{sub 4}){sub 2} single-crystalline fibers by the micro-pulling-down method

Journal Article · Thu Mar 15 04:00:00 EDT 2012 · Materials Research Bulletin

DOI:https://doi.org/10.1016/J.MATERRESBULL.2011.12.007· OSTI ID:22212464

Moraes, Jair Ricardo de ^[1]; Mazzocchi, Vera Lucia; Parente, Carlos Benedicto Ramos ^[1]; Courrol, Lilia Coronato ^[2]

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1. Instituto de Pesquisas Energeticas e Nucleares, IPEN - CNEN/SP, 05508-000 Sao Paulo, SP (Brazil)
2. Departamento de Ciencias Exatas e da Terra, Universidade Federal de Sao Paulo, UNIFESP, 09972-270 Diadema, SP (Brazil)

Highlights: Black-Right-Pointing-Pointer Transparent and uniform LiLa{sub (1-x)}Eu{sub x}(WO{sub 4}){sub 2} single-crystalline fibers were grown by the micro-pulling-down method. Black-Right-Pointing-Pointer Alkali and rare earth ionic radii influence the pulling rate on the growth. Black-Right-Pointing-Pointer Eu incorporation in LiLa(WO{sub 4}){sub 2} induces local distortions in the crystalline lattice. Black-Right-Pointing-Pointer LiLa{sub (1-x)}Eu{sub x}(WO{sub 4}){sub 2} single-crystalline fibers present intense red emission under 395 nm excitation. Black-Right-Pointing-Pointer Concentration quenching observed in the emission around 20 mol% of Eu doping. -- Abstract: Transparent and uniform LiLa{sub (1-x)}Eu{sub x}(WO{sub 4}){sub 2} single-crystalline fibers where x = 0.005, 0.01, 0.03, 0.05, 0.07, 0.1, 0.15, 0.2, 0.25 and 1.0, with an average of 20-40 mm length were obtained by the micro-pulling-down method aiming structural and optical characterization. The optimum pulling rate was found to depend on the difference between alkali and rare earth ionic radii. Rietveld analysis from X-ray diffraction data and excitation spectroscopy at room temperature were applied to investigate the lattice changes due to the Eu{sup 3+} incorporation in the host. LiLa{sub (1-x)}Eu{sub x}(WO{sub 4}){sub 2} crystal fibers present red emission due to the electric dipole {sup 5}D{sub 0} {yields} {sup 7}F{sub 2} transition under 395 nm excitation showing a concentration quenching around 20 mol% of doping. The excitation spectra of the {sup 7}F{sub 0} {yields} {sup 5}D{sub 0} transition show small changes in the Eu{sup 3+} surroundings as function of dopant concentration.

• OSTI ID: 22212464
• Journal Information: Materials Research Bulletin, Journal Name: Materials Research Bulletin Journal Issue: 3 Vol. 47; ISSN MRBUAC; ISSN 0025-5408
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CRYSTAL GROWTH
CRYSTAL STRUCTURE
ELECTRIC DIPOLES
EUROPIUM IONS
EXCITATION
FIBERS
LUMINESCENCE
MONOCRYSTALS
OPTICAL PROPERTIES
OXIDES
RARE EARTHS
SPECTROSCOPY
TUNGSTATES
X-RAY DIFFRACTION