Synthesis, characterization and magnetic properties of ultrafine Co{sub 3}O{sub 4} octahedra
- School of Chemistry, Trinity College, Dublin 2 (Ireland)
Octahedral Co{sub 3}O{sub 4} nanoparticles were synthesised in an aqueous ammonia solution using hexagonal β-Co(OH){sub 2} nanoplates as starting materials. Electron microscopy analysis indicates that the Co{sub 3}O{sub 4} particles have diameters of 20-40 nm and adopt a well-crystallized cubic spinel structure. The octahedral habit was verified by high angle annular dark field imaging. High resolution electron microscopy results revealed that the long axis of the octahedral Co{sub 3}O{sub 4} nanoparticles coincides with crystallographic <111> direction and the facets are the (111) planes. Magnetization measurements reveal antiferromagnetic ordering below 10 K, with a paramagnetic Curie temperature of 3 K and a paramagnetic susceptibility that is double that expected for high-spin Co{sup 2+}. The results show that a substantial fraction of the B-site Co{sup 3+} in the nanoparticles is in a high-spin state.
- OSTI ID:
- 22492302
- Journal Information:
- AIP Advances, Vol. 5, Issue 8; Other Information: (c) 2015 Author(s); Country of input: International Atomic Energy Agency (IAEA); ISSN 2158-3226
- Country of Publication:
- United States
- Language:
- English
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