Oxygen excess in the '114' cobaltite hexagonal structure: The ferrimagnet CaBaCo{sub 4}O{sub 7.50}
- Laboratoire CRISMAT, UMR 6508 CNRS ENSICAEN, 6 bd Marechal Juin, 14050 Caen (France)
The study of the oxidation of the '114' orthorhombic cobaltite CaBaCo{sub 4}O{sub 7}, using first electrochemistry and then soft chemistry based on oxidation by NaClO, has allowed a new phase, CaBaCo{sub 4}O{sub 7.50}, to be prepared topotactically. The structural study of this phase shows that its hexagonal structure, closely related to that of orthorhombic CaBaCo{sub 4}O{sub 7}, is curiously similar to that of the members of the LnBaCo{sub 4}O{sub 7} series, in spite of its excess oxygen. Its magnetic study shows that this phase, like CaBaCo{sub 4}O{sub 7}, is ferrimagnetic with the same T{sub C} (60 K), but differently exhibits an unusual magnetic hysteresis. This exceptional behavior of CaBaCo{sub 4}O{sub 7} with respect to oxidation as well as the magnetic properties of CaBaCo{sub 4}O{sub 7.50} is interpreted in terms of the presence of defects due to oxidation. - Graphical Abstract: The study of the oxidation of the '114' orthorhombic cobaltite CaBaCo{sub 4}O{sub 7}, using first electrochemistry and then soft chemistry based on oxidation by NaClO, has allowed a new phase, CaBaCo{sub 4}O{sub 7.50}, to be prepared topotactically. The structural study of this phase shows that its hexagonal structure, closely related to that of orthorhombic CaBaCo{sub 4}O{sub 7}, is curiously similar to that of the members of the LnBaCo{sub 4}O{sub 7} series, in spite of its oxygen excess. Its magnetic study shows that this phase, like CaBaCo{sub 4}O{sub 7}, is ferrimagnetic. Highlights: > Topotactic oxidation by means of electrochemistry and soft chemistry of the '114' orthorhombic cobaltite CaBaCo{sub 4}O{sub 7}. > This new phase, CaBaCo{sub 4}O{sub 7.5} shows an hexagonal structure, is closely related to that of orthorhombic mother phase CaBaCo{sub 4}O{sub 7}. > CaBaCo{sub 4}O{sub 7.5} is ferrimagnetic and exhibits an unusual magnetic hysteresis, due to defect pinning centers.
- OSTI ID:
- 21580255
- Journal Information:
- Journal of Solid State Chemistry, Vol. 184, Issue 9; Other Information: DOI: 10.1016/j.jssc.2011.07.039; PII: S0022-4596(11)00418-X; Copyright (c) 2011 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; ISSN 0022-4596
- Country of Publication:
- United States
- Language:
- English
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