Magnetoresistance in the ferromagnetic metallic perovskite SrFe1-xCoxO3

Citation
A. Maignan et al., Magnetoresistance in the ferromagnetic metallic perovskite SrFe1-xCoxO3, SOLID ST SC, 3(1-2), 2001, pp. 57-63
Citations number
16
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science
Journal title
SOLID STATE SCIENCES
ISSN journal
12932558 → ACNP
Volume
3
Issue
1-2
Year of publication
2001
Pages
57 - 63
Database
ISI
SICI code
1293-2558(200101/02)3:1-2<57:MITFMP>2.0.ZU;2-G
Abstract
The investigation of the magnetic and transport properties of the oxygen de ficient perovskites SrFe1-xCoxO3-delta shows that these compounds exhibit b oth ferromagnetism and metallicity in a wide compositional range (0 less th an or equal to x less than or equal to 0.70). Negative magnetoresistance is evidenced for the first time in these oxides, in contrast to SrCoO3-delta. These properties are explained by superexchange interactions between cobal t and iron according to the scheme Fe3+-O-Co4+ <----> Fe4+-O-Co3+. This mod el is strongly supported by Fe-57 Mossbauer measurements which show the exi stence of two sites at room temperature, high spin localized Fe4+ and deloc alized Fe3+alpha sites, whereas magnetic disordering suggesting spin fluctu ations is observed at 5 K as soon as cobalt is introduced into the SrFeO3 s tructure. (C) 2001 Editions scientifiques et medicales Elsevier SAS. All ri ghts reserved.