HREM of the [111] surfaces of iron oxide nanoparticles.

Mixed phase Fe3O4-gamma-Fe2O3 (magnetite-maghemite) iron oxide nanoparticles have been fabricated by colloidal routes. HRTEM/HRSTEM images of the nanoparticles show the presence of [111] facets that terminate with enhanced contrast, which is shown to be caused by the presence of additional cations a...

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Main Authors: Lovely, G, Brown, A, Brydson, R, Kirkland, A, Meyer, R, Chang, L, Jefferson, D, Falke, M, Bleloch, A
Format: Conference item
Published: 2006
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author Lovely, G
Brown, A
Brydson, R
Kirkland, A
Meyer, R
Chang, L
Jefferson, D
Falke, M
Bleloch, A
author_facet Lovely, G
Brown, A
Brydson, R
Kirkland, A
Meyer, R
Chang, L
Jefferson, D
Falke, M
Bleloch, A
author_sort Lovely, G
collection OXFORD
description Mixed phase Fe3O4-gamma-Fe2O3 (magnetite-maghemite) iron oxide nanoparticles have been fabricated by colloidal routes. HRTEM/HRSTEM images of the nanoparticles show the presence of [111] facets that terminate with enhanced contrast, which is shown to be caused by the presence of additional cations at the edges of the nanoparticles. HRTEM images were taken on a FEI CM200 FEGTEM, a JEOL 3100 with a LaB6 source, and a double aberration corrected JEOL-JEM 2200FS FEGTEM. The enhanced contrast effect was observed on the [111] surface atomic layers resolved using each machine. HRSTEM images, taken on an aberration corrected STEM, resolved enhanced contrast at specific surface sites. Exit wave reconstruction was also carried out on focal series taken on a double aberration corrected JEOL-JEM 2200FS and showed similar highly resolved enhanced contrast at specific surface cation sites. It is apparent that additional cations are occupying the [111] terminating layers of these nanoparticle surfaces. The use of different microscopes and techniques in this paper provides strong evidence that the enhanced contrast is a real effect and not an effect caused by microscope aberrations.
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spelling oxford-uuid:5fafb5fd-9bff-4967-af8a-cff752eda2222022-03-26T17:48:34ZHREM of the [111] surfaces of iron oxide nanoparticles.Conference itemhttp://purl.org/coar/resource_type/c_5794uuid:5fafb5fd-9bff-4967-af8a-cff752eda222Symplectic Elements at Oxford2006Lovely, GBrown, ABrydson, RKirkland, AMeyer, RChang, LJefferson, DFalke, MBleloch, AMixed phase Fe3O4-gamma-Fe2O3 (magnetite-maghemite) iron oxide nanoparticles have been fabricated by colloidal routes. HRTEM/HRSTEM images of the nanoparticles show the presence of [111] facets that terminate with enhanced contrast, which is shown to be caused by the presence of additional cations at the edges of the nanoparticles. HRTEM images were taken on a FEI CM200 FEGTEM, a JEOL 3100 with a LaB6 source, and a double aberration corrected JEOL-JEM 2200FS FEGTEM. The enhanced contrast effect was observed on the [111] surface atomic layers resolved using each machine. HRSTEM images, taken on an aberration corrected STEM, resolved enhanced contrast at specific surface sites. Exit wave reconstruction was also carried out on focal series taken on a double aberration corrected JEOL-JEM 2200FS and showed similar highly resolved enhanced contrast at specific surface cation sites. It is apparent that additional cations are occupying the [111] terminating layers of these nanoparticle surfaces. The use of different microscopes and techniques in this paper provides strong evidence that the enhanced contrast is a real effect and not an effect caused by microscope aberrations.
spellingShingle Lovely, G
Brown, A
Brydson, R
Kirkland, A
Meyer, R
Chang, L
Jefferson, D
Falke, M
Bleloch, A
HREM of the [111] surfaces of iron oxide nanoparticles.
title HREM of the [111] surfaces of iron oxide nanoparticles.
title_full HREM of the [111] surfaces of iron oxide nanoparticles.
title_fullStr HREM of the [111] surfaces of iron oxide nanoparticles.
title_full_unstemmed HREM of the [111] surfaces of iron oxide nanoparticles.
title_short HREM of the [111] surfaces of iron oxide nanoparticles.
title_sort hrem of the 111 surfaces of iron oxide nanoparticles
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