Advanced search
Start date
Betweenand
(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Network Structure and Rare-Earth Ion Local Environments in Fluoride Phosphate Photonic Glasses Studied by Solid-State NMR and Electron Paramagnetic Resonance Spectroscopies

Full text
Author(s):
de Oliveira, Jr., Marcos [1] ; Uesbeck, Tobias [2] ; Goncalves, Tassia S. [1] ; Magon, Claudio Jose [1] ; Pizani, Paulo S. [3] ; de Camargo, Andrea S. S. [1] ; Eckert, Hellmut [1, 2]
Total Authors: 7
Affiliation:
[1] Univ Sao Paulo, Inst Fis Sao Carlos, BR-13566590 Sao Carlos, SP - Brazil
[2] Univ Munster, Inst Phys Chem, D-48149 Munster - Germany
[3] Univ Fed Sao Carlos, Dept Fis, BR-13566590 Sao Carlos, SP - Brazil
Total Affiliations: 3
Document type: Journal article
Source: Journal of Physical Chemistry C; v. 119, n. 43, p. 24574-24587, OCT 29 2015.
Web of Science Citations: 19
Abstract

A detailed structural investigation of a series of fluoride phosphate laser glasses with nominal composition 25BaF(2)-25SrF(2)-(30 - x)Al(PO3)(3)-xAlF(3)-(20-z)YF3:zREF(3) with x = 25, 20, 15 and 10, RE = Yb and Eu, and 0 <= z <= 1.0 has been conducted using Raman, solid-state nuclear magnetic resonance (NMR), and electron paramagnetic resonance (EPR) spectroscopies. The network structure is dominated by the preferred formation of aluminum-to-phosphorus linkages, which have been quantified by means of Al-27/P-31 NMR double-resonance techniques. The fluoride ions are found in mixed Al/Y/Ba/Sr environments accommodating the luminescent dopant species as well. The local environments of the rare-earth species have been studied by pulsed EPR spectroscopy of the Yb3+ spin probe (S = 1/2), revealing composition-dependent echo-detected lineshapes and strong hyperfme coupling with F-19 nuclei in hyperfine sublevel correlation (HYSCORE) spectra consistent with the formation of Yb3+-F bonds. In addition, photoluminescence spectra of Eu3+-doped samples reveal that the D-5(0) -> F-7(2)/D-5(0) -> F-7(1) transitions intensity ratio, the normalized phonon sideband intensities in the excitation spectra, and excited state D-5(0) lifetime values are systematically dependent on fluoride content. Altogether, these results indicate that the rare-earth ions are found in a mixed fluoride/phosphate environment, to which the fluoride ions make the dominant contribution. Nevertheless, even at the highest fluoride levels (x = 25), the data suggest residual rare-earth phosphate coordination. (AU)

FAPESP's process: 13/23490-3 - Magnetic resonance techniques for the study of Structure/Property correlations in photonic glassy and glass ceramic materials
Grantee:Marcos de Oliveira Junior
Support type: Scholarships in Brazil - Post-Doctorate
FAPESP's process: 13/07793-6 - CEPIV - Center for Teaching, Research and Innovation in Glass
Grantee:Edgar Dutra Zanotto
Support type: Research Grants - Research, Innovation and Dissemination Centers - RIDC