The solubility of Co in TiO{sub 2} anatase and rutile and its effect on the magnetic properties

Journal Article · Wed Apr 15 00:00:00 EDT 2009 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2009.01.011· OSTI ID:21370360

Fleischhammer, Meike; Panthoefer, Martin ^[1]; Tremel, Wolfgang ^[1]

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1. Institut fuer Anorganische Chemie und Analytische Chemie, Johannes Gutenberg-Universitaet Mainz, Duesbergweg 10-14, 55099 Mainz (Germany)

Co-doped anatase and rutile bulk-samples prepared by the sol-gel technique are found to be paramagnetic at room-temperature. Only further annealing in Ar/H{sub 2} gas results in a ferromagnetic behavior. X-ray diffraction and electron-microscope studies reveal for low doping levels <4% the formation of Co-doped rutile samples and the formation of CoTiO{sub 3} as a new phase. Co{sub 3}O{sub 4} can be detected in anatase samples with Co doping levels >=4%. The observed Co oxides are reduced by Ar/H{sub 2} to Co metal. The room-temperature ferromagnetism can therefore be traced back to a segregation of metallic Co. - Graphical abstract: Co-doped anatase and rutile bulk-samples prepared by the sol-gel technique are paramagnetic at room-temperature. Further annealing in Ar/H{sub 2} gas results in a ferromagnetic behavior. X-ray diffraction and electron-microscope (SEM, BSE) studies reveal for low doping levels <4% the formation of Co-doped rutile samples and of CoTiO{sub 3} as a new phase. Co{sub 3}O{sub 4} is found in anatase samples with Co doping levels >=4%. The observed Co oxides are reduced by Ar/H{sub 2} to Co metal. The room-temperature ferromagnetism can be traced back to a segregation of metallic Co

• OSTI ID: 21370360
• Journal Information: Journal of Solid State Chemistry, Vol. 182, Issue 4; Other Information: DOI: 10.1016/j.jssc.2009.01.011; PII: S0022-4596(09)00019-X; Copyright (c) 2009 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ANNEALING
COBALT OXIDES
DOPED MATERIALS
ELECTRON MICROSCOPES
FERROMAGNETISM
MAGNETIC PROPERTIES
PARAMAGNETISM
RUTILE
SCANNING ELECTRON MICROSCOPY
SEGREGATION
SOL-GEL PROCESS
SOLUBILITY
TEMPERATURE RANGE 0273-0400 K
TITANATES
TITANIUM OXIDES
X-RAY DIFFRACTION
CHALCOGENIDES
COBALT COMPOUNDS
COHERENT SCATTERING
DIFFRACTION
ELECTRON MICROSCOPY
HEAT TREATMENTS
MAGNETISM
MATERIALS
MICROSCOPES
MICROSCOPY
MINERALS
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
RADIOACTIVE MATERIALS
RADIOACTIVE MINERALS
SCATTERING
TEMPERATURE RANGE
TITANIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS