Open AccessSynthesis, characterization and magnetic properties of ultrafine Co3O4 octahedra
Author(s) -
Y. H. Chen,
Junfeng Zhou,
Daragh Mullarkey,
Robert O’Connell,
Wolfgang Schmitt,
M. Venkatesan,
J. M. D. Coey,
Hongzhou Zhang
Publication year - 2015
Publication title -
aip advances
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.421
H-Index - 58
ISSN - 2158-3226
DOI - 10.1063/1.4928494
Subject(s) - octahedron , spinel , paramagnetism , crystallography , materials science , magnetization , antiferromagnetism , transmission electron microscopy , high resolution transmission electron microscopy , nanoparticle , condensed matter physics , chemistry , crystal structure , nanotechnology , magnetic field , metallurgy , physics , quantum mechanics
Octahedral Co3O4 nanoparticles were synthesised in an aqueous ammonia solution using hexagonal β-Co(OH)2 nanoplates as starting materials. Electron microscopy analysis indicates that the Co3O4 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 Co3O4 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 Co2+. The results show that a substantial fraction of the B-site Co3+ in the nanoparticles is in a high-spin state
Accelerating Research
Robert Robinson Avenue,
Oxford Science Park, Oxford
OX4 4GP, United Kingdom
Address
John Eccles HouseRobert Robinson Avenue,
Oxford Science Park, Oxford
OX4 4GP, United Kingdom