scholarly journals Investigation on cation distribution and luminescence in spinel phase γ-Ga3−δO4 : Sm nanostructures using X-ray absorption spectroscopy

RSC Advances ◽  
2017 ◽  
Vol 7 (83) ◽  
pp. 52543-52554 ◽  
Author(s):  
Aditya Sharma ◽  
Mayora Varshney ◽  
Hyun-Joon Shin ◽  
Keun Hwa Chae ◽  
Sung Ok Won

In this study, spectroscopic investigations are employed to quantify the Ga distribution over the tetrahedral/octahedral sites and to assimilate the luminescence properties in the barely reported γ-Ga2.67O4 : Sm nanoparticles.

2014 ◽  
Author(s):  
A. K. Yadav ◽  
J. Jadhav ◽  
S. Biswas ◽  
S. N. Jha ◽  
D. Bhattacharyya ◽  
...  

2018 ◽  
Vol 6 (4) ◽  
pp. 875-882 ◽  
Author(s):  
A. Fraile Rodríguez ◽  
C. Moya ◽  
M. Escoda-Torroella ◽  
A. Romero ◽  
A. Labarta ◽  
...  

Single-particle X-ray absorption spectroscopy reveals that the oxidation state and cation distribution of individual magnetite nanoparticles may be largely heterogeneous even when the macroscopic structural and magnetic response of the ensembles is uniform.


2015 ◽  
Vol 79 (3) ◽  
pp. 635-647 ◽  
Author(s):  
G. D. Bromiley ◽  
G. D. Gatta ◽  
T. Stokes

AbstractManganese incorporation in synthetic hercynite, and partitioning between hercynite and silicate melt synthesized at 1.0 GPa, 1250°C, and at an fO2 buffered by Fe–FeO, has been studied by X-ray absorption spectroscopy and single-crystal X-ray structure refinement. Spectra indicate the presence of both Mn2+ and Mn3+ (and possibly also Mn4+) in synthetic hercynite and partitioning of Mn2+ into the melt phase, and Mn3+ into hercynite, respectively, under run conditions. X-ray refinement is consistent with partial disorder of Fe and Al across tetrahedral and octahedral sites. A higher than expected degree of Fe-Al disorder in the Mn-bearing hercynite can be explained by preferential incorporation of Mn2+ onto the tetrahedral site, and indicates that Fe-Al disorder in pure, stoichiometric hercynite cannot necessarily be used to determine closure temperatures in natural spinel. However, partitioning of Mn2+ and Mn3+ between melt and hercynite suggests that Mn incorporation in hercynite could be used as a measure of fO2 conditions in magmas during spinel crystallization.


2016 ◽  
Vol 16 (10) ◽  
pp. 1342-1348 ◽  
Author(s):  
Aditya Sharma ◽  
Mayora Varshney ◽  
Hyun Joon Shin ◽  
Keun Hwa Chae ◽  
Sung Ok Won

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