Insights into the structural variations in SmNb1−xTaxO4 and HoNb1−xTaxO4 combined experimental and computational studies

Simple item page
dc.contributor.authorMullens, BGen_AU
dc.contributor.authorAvdeev, Men_AU
dc.contributor.authorBrand, HEAen_AU
dc.contributor.authorMondal, Sen_AU
dc.contributor.authorVaitheeswaran, Gen_AU
dc.contributor.authorKennedy, BJen_AU
dc.date.accessioned2021-09-14T00:41:02Zen_AU
dc.date.available2021-09-14T00:41:02Zen_AU
dc.date.issued2021-06-01en_AU
dc.date.statistics2021-09-07en_AU
dc.description.abstractThe impact of Ta doping on two orthoniobates SmNbO4 and HoNbO4 has been studied using a combination of high-resolution powder diffraction and Density-Functional Theory calculations. In both ANb1−xTaxO4 (A = Sm, Ho) series the unit cell volume decreases as the Ta content increased demonstrating that the effective ionic radii of Ta is smaller than that of Nb in this structure. The average Sm–O distance and volume of the SmO8 polyhedra were invariant of the Ta content across the SmNb1−xTaxO4 solid solution whereas the average M–O (M = Nb or Ta) distance and MO6 polyhedral volume decrease with Ta doping. The analogous Ho oxides HoNb1−xTaxO4 do not form a complete solid solution when the samples were prepared at 1400 °C, rather there is a miscibility gap around x = 0.95, with HoTaO4 exhibiting the M′-type P2/c structure rather than the M-type I2/a structure of HoNbO4. Increasing the synthesis temperature to 1450 °C eliminates the miscibility gap. The energy difference between the P2/c and I2/a structures of HoTaO4 is found to be nearly 30 meV per f.u. with the total energy of the P2/c phase of HoTaO4 being more negative. First-principles calculations, carried out using Density-Functional Theory, reveal significant covalent character in the Nb–O bonds, which is reduced in the corresponding tantalates. Anisotropy in the Born Effective Charge tensors demonstrates the impact of the long M–O bond identified in the structural studies showing that the Nb and Ta cations are effectively six-coordinate. The similarity in the frequency of the intense Raman peak near 800 cm−1 due to the symmetric stretching of the Ta–O bonds is consistent with the description of that both polymorphs of HoTaO4 contain TaO6 octahedra. © The Royal Society of Chemistry 2021en_AU
dc.identifier.citationMullens, B. G., Avdeev, M., Brand, H. E. A., Mondal, S., Vaitheeswaran, G., & Kennedy, B. J. (2021). Insights into the structural variations in SmNb1−xTaxO4 and HoNb1−xTaxO4 combined experimental and computational studies. Dalton Transactions, 50(26), 9103-9117. doi:10.1039/D1DT01051Den_AU
dc.identifier.issn1477-9234en_AU
dc.identifier.issue26en_AU
dc.identifier.journaltitleDalton Transactionsen_AU
dc.identifier.pagination9103-9117en_AU
dc.identifier.urihttps://doi.org/10.1039/D1DT01051Den_AU
dc.identifier.urihttps://apo.ansto.gov.au/dspace/handle/10238/11691en_AU
dc.identifier.volume50en_AU
dc.language.isoenen_AU
dc.publisherRoyal Society of Chemistryen_AU
dc.subjectDiffractionen_AU
dc.subjectDopingen_AU
dc.subjectOxidesen_AU
dc.subjectDensity functional methoden_AU
dc.subjectAnisotropyen_AU
dc.subjectPhotocatalysisen_AU
dc.subjectRadioactive waste storageen_AU
dc.titleInsights into the structural variations in SmNb1−xTaxO4 and HoNb1−xTaxO4 combined experimental and computational studiesen_AU
dc.typeJournal Articleen_AU
Files
License bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
license.txt
Size:
1.63 KB
Format:
Item-specific license agreed upon to submission
Description:
Download
Collections
Journal Articles