Structure of ultraphosphate glasses with small rare-earth ions by X-ray diffraction

Hoppe, Uwe; Wyckoff, N.P.; Brow, Richard K.; Rütt, U.

doi:10.1016/j.jnoncrysol.2010.12.057

Cited by 3 publications

(10 citation statements)

References 39 publications

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“…13,14 The small Al contamination resulted in a correspondingly small additional feature in t(r) being found at an atomic separation of 1. samples. These values are largely consistent with those found in literature, [11][12][13][14][15][16][17][18] noting that some uncertainty arises in the estimation of the coordination numbers for all samples due to the effects of overlapping correlations. The coordination numbers of this correlation varied considerably, which is likely to be due, in part, to the assumed weight fraction; this variation may also arise from the consideration that three distinct Al 3+ structural configurations are possible which feature 4-, 5-, or 6-fold coordinations.…”

Section: Co-doped Rare-earth Phosphate Glassessupporting

confidence: 91%

“…The motivation behind this enquiry was the idea that there might be significant structural variation in the immediate rare-earth environment, which might then filter into the phosphate network as well. [11][12][13][14][15] The immediate rare-earth environment therefore depends on ionic size; 11 results also evidenced rare-earth clustering in glasses with seven-coordinate R 3+ environments where compositions were close to the metaphosphate limit. [11][12][13][14][15] The immediate rare-earth environment therefore depends on ionic size; 11 results also evidenced rare-earth clustering in glasses with seven-coordinate R 3+ environments where compositions were close to the metaphosphate limit.…”

Section: Introductionmentioning

confidence: 95%

“…[11][12][13][14][15] The immediate rare-earth environment therefore depends on ionic size; 11 results also evidenced rare-earth clustering in glasses with seven-coordinate R 3+ environments where compositions were close to the metaphosphate limit. [11][12][13][14][15][16][17][18] Meanwhile, the closest RÁ Á ÁR separation was probed by anomalous dispersion neutron diffraction (R = Sm, x = 0.205), 27 and a magnetic difference neutron diffraction experiment (R = Tb, x = 0.246), 28 revealing minimum RÁ Á ÁR distances of B4 and 3.9 Å, respectively. [11][12][13][14][15][16][17][18] Meanwhile, the closest RÁ Á ÁR separation was probed by anomalous dispersion neutron diffraction (R = Sm, x = 0.205), 27 and a magnetic difference neutron diffraction experiment (R = Tb, x = 0.246), 28 revealing minimum RÁ Á ÁR distances of B4 and 3.9 Å, respectively.…”

Section: Introductionmentioning

confidence: 95%

“…Furthermore, Zhang et al 7 reported that lasing performance was much stronger in the co-doped glass than in glass doped with erbium alone. [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] However, these studies have focused on glasses containing only one rare-earth type; the effect of co-doping on the local structure would therefore be of substantial interest. Given the inherent relationship between the local structure and its optoelectronic properties, the local structure of rare-earth phosphate glasses has been studied in some detail.…”

Section: Introductionmentioning

confidence: 99%

“…[11][12][13][14][15][16][17][18] The nature of the nearest-neighbour RÁ Á ÁR separation has also garnered much attention owing to the recognition that the closest approach between rare-earth ions has a large effect on the physical properties of the glass: if the R 3+ ions are too close together, the optical and magnetic properties of the glass become impeded. [11][12][13][14][15][16][17][18] The nature of the nearest-neighbour RÁ Á ÁR separation has also garnered much attention owing to the recognition that the closest approach between rare-earth ions has a large effect on the physical properties of the glass: if the R 3+ ions are too close together, the optical and magnetic properties of the glass become impeded.…”

Section: Introductionmentioning

confidence: 99%

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Effects of rare-earth co-doping on the local structure of rare-earth phosphate glasses using high and low energy X-ray diffraction

Cramer

Cole

FitzGerald

et al. 2013

Phys. Chem. Chem. Phys.

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Rare-earth co-doping in inorganic materials has a long-held tradition of facilitating highly desirable optoelectronic properties for their application to the laser industry. This study concentrates specifically on rare-earth phosphate glasses, (R2O3)x(R'2O3)y(P2O5)(1-(x+y)), where (R, R') denotes (Ce, Er) or (La, Nd) co-doping and the total rare-earth composition corresponds to a range between metaphosphate, RP3O9, and ultraphosphate, RP5O14. Thereupon, the effects of rare-earth co-doping on the local structure are assessed at the atomic level. Pair-distribution function analysis of high-energy X-ray diffraction data (Q(max) = 28 Å(-1)) is employed to make this assessment. Results reveal a stark structural invariance to rare-earth co-doping which bears testament to the open-framework and rigid nature of these glasses. A range of desirable attributes of these glasses unfold from this finding; in particular, a structural simplicity that will enable facile molecular engineering of rare-earth phosphate glasses with 'dial-up' lasing properties. When considered together with other factors, this finding also demonstrates additional prospects for these co-doped rare-earth phosphate glasses in nuclear waste storage applications. This study also reveals, for the first time, the ability to distinguish between P-O and P[double bond, length as m-dash]O bonding in these rare-earth phosphate glasses from X-ray diffraction data in a fully quantitative manner. Complementary analysis of high-energy X-ray diffraction data on single rare-earth phosphate glasses of similar rare-earth composition to the co-doped materials is also presented in this context. In a technical sense, all high-energy X-ray diffraction data on these glasses are compared with analogous low-energy diffraction data; their salient differences reveal distinct advantages of high-energy X-ray diffraction data for the study of amorphous materials.

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