Local structure and oxide-ion conduction mechanism in apatite-type lanthanum silicates
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چکیده
منابع مشابه
Local structure and oxide-ion conduction mechanism in apatite-type lanthanum silicates
The local structure of apatite-type lanthanum silicates of general formula La9.33+x(SiO4)6O2+3x/2 has been investigated by combining the atomic pair distribution function (PDF) method, conventional X-ray and neutron powder diffraction (NPD) data and density functional theory (DFT) calculations. DFT was used to build structure models with stable positions of excess oxide ions within the conducti...
متن کاملAtomic-scale mechanistic features of oxide ion conduction in apatite-type germanates.
Atomistic modelling studies of the apatite-type oxide ion conductor La9.33(GeO4)6O2 show that a key role of the O4 channel oxygen atoms appears to be as a reservoir for the creation of interstitial oxide ion defects, while the migration of these defects proceeds via the GeO4 tetrahedra.
متن کاملNeutron diffraction and atomistic simulation studies of Mg doped apatite-type oxide ion conductors.
In this paper, detailed studies of the effect of Mg doping in the apatite-type oxide ion conductor La9.33Si6O26 are reported. Mg is confirmed as an ambisite dopant, capable of substituting for both La and Si, depending on the starting composition. A large enhancement in the conductivity is observed for Si site substitution, with a reduction for substitution on the La site. Neutron powder diffra...
متن کاملStructural studies of apatite-type oxide ion conductors doped with cobalt.
A series of Co doped lanthanum silicate apatite-type phases, La9.83Si4.5Co1.5O26, La9.66Si5CoO26, La10Si5CoO26.5 and La8BaCoSi6O26, have been synthesised, and neutron diffraction, EXAFS and XANES used to investigate their structures in detail. All compositions were shown to possess the hexagonal apatite structure, and the results confirmed that cobalt can be doped onto both the La and Si sites ...
متن کاملSynthesis of hexagonal lanthanum germanate apatites through site selective isovalent doping with yttrium
2 Abstract Apatite-type lanthanum silicates/germanates have been attracting considerable interest as a new class of oxide ion conductors, whose conductivity is mediated by oxide ion interstititials. For the germanates, it has been shown that, depending on composition, the cell can be either hexagonal or triclinic, with evidence for reduced low temperature conductivities for the latter, attribut...
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ژورنال
عنوان ژورنال: Science and Technology of Advanced Materials
سال: 2017
ISSN: 1468-6996,1878-5514
DOI: 10.1080/14686996.2017.1362939