Issue
J. Phys. IV France
Volume 07, Number C1, Mars 1997
7th INTERNATIONAL CONFERENCE ON FERRITES
Page(s) C1-351 - C1-352
DOI https://doi.org/10.1051/jp4:19971142
7th INTERNATIONAL CONFERENCE ON FERRITES

J. Phys. IV France 07 (1997) C1-351-C1-352

DOI: 10.1051/jp4:19971142

Mössbauer Characteristics of the Nonstoichiometric Sr2LaFe3O8+δ Perovskite Obtained by Electrochemical Oxidation

A. Wattiaux, L. Fournès, F. Zhou, J.C. Grenier, M. Pouchard and J. Etourneau

Institut de Chimie de la Matière Condensée de Bordeaux, avenue du Dr. A. Schweitzer, 33608 Pessac cedex, France


Abstract
The nonstoichiometry and the vacancy ordering in the perovskite Ca2LaFe3O8 has been investigated in previous works [1,2]. More recently, the occurrence of a large nonstoichiometric domain has been shown in the Sr2LaFe3O8+δ system [3]. Thus, we have used a new "Chimie Douce" method : electrochemical oxidation which has been developped in our laboratory [4] for obtaining Sr2LaFe3O8.90 in alkaline medium. The starting material Sr2LaFe3O8 has been characterized by XRD, chemical analysis and Mössbauer spectroscopy. This compound contains only Fe3+. The Mössbauer spectroscopy reveals, in the oxidized phase, the occurrence of antiferromagnetic interaction below TN = 195 K with a good agreement with electric and magnetic measurements. At low temperature, the presence of two sextets can be explained in terms of a charge disproportionation :
2 Fe 4+ → Fe(4-λ)+ + Fe(4+λ)+ .



© EDP Sciences 1997