Cation distribution and magnetic structure of the ferrimagnetic spinel NiCO₂O₄

JF Marco; JR Gancedo; M Gracia; JL Gautier; EI Rios; Helen Palmer; Colin Greaves; Frank Berry

doi:10.1039/b103135j

Cation distribution and magnetic structure of the ferrimagnetic spinel NiCO₂O₄

JF Marco, JR Gancedo, M Gracia, JL Gautier, EI Rios, Helen Palmer, Colin Greaves, Frank Berry

Chemistry

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Abstract

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+.

Original language	English
Pages (from-to)	3087-3093
Number of pages	7
Journal	Journal of Materials Chemistry
Volume	11
DOIs	https://doi.org/10.1039/b103135j
Publication status	Published - 1 Jan 2001

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title = "Cation distribution and magnetic structure of the ferrimagnetic spinel NiCO₂O₄",

abstract = "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+.",

author = "JF Marco and JR Gancedo and M Gracia and JL Gautier and EI Rios and Helen Palmer and Colin Greaves and Frank Berry",

year = "2001",

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doi = "10.1039/b103135j",

language = "English",

volume = "11",

pages = "3087--3093",

journal = "Journal of Materials Chemistry",

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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+.

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U2 - 10.1039/b103135j

DO - 10.1039/b103135j

M3 - Article

VL - 11

SP - 3087

EP - 3093

JO - Journal of Materials Chemistry

JF - Journal of Materials Chemistry

ER -

Cation distribution and magnetic structure of the ferrimagnetic spinel NiCO₂O₄

Abstract

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