TY - JOUR
T1 - Cation distribution and magnetic structure of the ferrimagnetic spinel NiCO₂O₄
AU - Marco, JF
AU - Gancedo, JR
AU - Gracia, M
AU - Gautier, JL
AU - Rios, EI
AU - Palmer, Helen
AU - Greaves, Colin
AU - Berry, Frank
PY - 2001/1/1
Y1 - 2001/1/1
N2 - The compound NiCo2O4, with spinel-related structure, has been prepared by thermal decomposition of metal nitrates and its bulk structural properties examined by means of magnetic measurements, neutron diffraction, X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS). The results suggest a delocalised electron distribution on the octahedral sites with average oxidation states of +3.5 and +2.5 for nickel and cobalt, respectively, and lead to a cation distribution for NiCo2O4 of {Ni0.13+Co0.92+}(tet)[Ni0.93.5+Co1.12.5+](oct)O-4. This electronic configuration is consistent with magnetisation measurements if applied magnetic fields cause a charge redistribution on the octahedral sites to favour Co3+ and Ni3+. The surface of NiCo2O4 was examined by X-ray photoelectron spectroscopy (XPS) and found to have a different composition containing Co2+, Co3+, Ni2+, Ni3+ and, probably, Ni4+.
AB - The compound NiCo2O4, with spinel-related structure, has been prepared by thermal decomposition of metal nitrates and its bulk structural properties examined by means of magnetic measurements, neutron diffraction, X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS). The results suggest a delocalised electron distribution on the octahedral sites with average oxidation states of +3.5 and +2.5 for nickel and cobalt, respectively, and lead to a cation distribution for NiCo2O4 of {Ni0.13+Co0.92+}(tet)[Ni0.93.5+Co1.12.5+](oct)O-4. This electronic configuration is consistent with magnetisation measurements if applied magnetic fields cause a charge redistribution on the octahedral sites to favour Co3+ and Ni3+. The surface of NiCo2O4 was examined by X-ray photoelectron spectroscopy (XPS) and found to have a different composition containing Co2+, Co3+, Ni2+, Ni3+ and, probably, Ni4+.
UR - http://www.scopus.com/inward/record.url?scp=0035668160&partnerID=8YFLogxK
U2 - 10.1039/b103135j
DO - 10.1039/b103135j
M3 - Article
SN - 0959-9428
VL - 11
SP - 3087
EP - 3093
JO - Journal of Materials Chemistry
JF - Journal of Materials Chemistry
ER -