Widatallah, H. M.; Al-Harthi, S. H.; Johnson, C.; Klencsár, Z.; Gimelseed, A. M.; Moore, E. A. ; Al-Rawas, A. D.; Wynter, C. I. and Brown, D. E.
|DOI (Digital Object Identifier) Link:||http://doi.org/10.1088/0022-3727/44/26/265403|
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Nanocrystalline EuCrO3 particles (~25 nm) have been prepared by pre-milling a 1 : 1 molar mixture of Eu2O3 and Cr2O3 for 60 h followed by sintering at 700°C (12 h). This temperature is ~500–600°C lower than those at which the material, in bulk form, is conventionally prepared. Rietveld analysis of the x-ray powder diffraction pattern of the EuCrO3 nanoparticles favours a structural model involving a slight degree of cationic exchange where ~11% of the Eu3+ and Cr3+ ions exchange their normal dodecahedral A- and octahedral B-sites, respectively, in the perovskite-related structure. This cationic site exchange, which is unusual in a perovskite structure, has been well supported by the corresponding room-temperature 151Eu Mössbauer spectrum of the nanoparticles that in addition to displaying a distribution in the principal component of the EFG tensor (Vzz) at the usual A-sites of the 151Eu nuclei, also revealed the presence of a subcomponent with ~11% area fraction and a considerably increased |Vzz| value that was associated with Eu3+ ions at octahedral B-sites. X-ray photoelectron and Auger electron spectroscopic techniques reveal a complex surface structure where extremely thin layers of un-reacted Eu2O3 and Cr2O3 cover most of the EuCrO3 nanoparticles' surfaces together with some traces of elemental Cr. The binding energies associated with Eu3+ 3d5/2, Eu3+ 4d3/2, Cr3+ 2p3/2 and O2− 1s core-level electrons in EuCrO3 are estimated from the x-ray photoelectron data for the first time.
|Item Type:||Journal Article|
|Copyright Holders:||2011 IOP Publishing Ltd.|
|Project Funding Details:||
|Academic Unit/Department:||Faculty of Science, Technology, Engineering and Mathematics (STEM) > Life, Health and Chemical Sciences
Faculty of Science, Technology, Engineering and Mathematics (STEM)
|Interdisciplinary Research Centre:||Centre for Earth, Planetary, Space and Astronomical Research (CEPSAR)
Biomedical Research Network (BRN)
|Depositing User:||Elaine Moore|
|Date Deposited:||19 Jul 2011 16:30|
|Last Modified:||04 Oct 2016 11:04|
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