Very high coercivity of distorted spinel iron manganites. Example of mixed-valence defect oxide Mn1.7Fe1.3O4+delta.

Authors
Agnoli, F Albouy, B Tailhades, P Rousset, A
Citation
F. Agnoli et al., Very high coercivity of distorted spinel iron manganites. Example of mixed-valence defect oxide Mn1.7Fe1.3O4+delta., CR AC S IIC, 2(9-10), 1999, pp. 525-530
Citations number
9
Categorie Soggetti
Chemistry
Journal title
COMPTES RENDUS DE L ACADEMIE DES SCIENCES SERIE II FASCICULE C-CHIMIE
ISSN journal
13871609 → ACNP
Volume
2
Issue
9-10
Year of publication
1999
Pages
525 - 530
Database
ISI
SICI code
1387-1609(199909/10)2:9-10<525:VHCODS>2.0.ZU;2-I
Abstract
MnxFe3-xO4 (x = 1.00, 1.21, 1.50, 1.70) spinels with acicular shape have be en prepared from oxalic precursors. Due to their state of division, these f errites can be oxidized at moderate temperatures into mixed-valence defect spinels MnxFe3-xO4+delta. These phases can exhibit a high content of Mn3+ i ons which are responsible for changes in crystalline structure, the lattice becoming tetragonal. The coercive force of tetragonal spinels increases wi th the cia ratio of the unit cell parameters. Coercivities of about 4 000 O e were reached. (C) 1999 Academie des sciences/Editions scientifiques et: m edicales Elsevier SAS.