Spin State Transition in LaCoO3 with Temperature or Strontium Doping as Seen by XAS
✍ Scribed by O. Toulemonde; N. N'Guyen; F. Studer; A. Traverse
- Publisher
- Elsevier Science
- Year
- 2001
- Tongue
- English
- Weight
- 405 KB
- Volume
- 158
- Category
- Article
- ISSN
- 0022-4596
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✦ Synopsis
An X-ray absorption spectroscopy study of the polycrystalline La 1؊x Sr x CoO 3 (x ؍ 0, 0.25, 0.5) series at O K-edge was performed above and below the various magnetic transition temperatures. A crystal 5eld analysis is proposed to explain the observed 5ne structure changes. Temperature-dependent O Kedge of LaCoO 3 shows evidence of smooth and continuous spin transition of Co 3؉ from low to intermediate spin states. This result is con5rmed by cobalt K-edge measurements. Upon strontium doping, O K-edges of the La 1؊x Sr x CoO 3 (x ,0؍ 0.25, 0.5) series suggested a mixed (LS+IS) Co 3؉ /IS Co 4؉ cobalt ion con5guration. The fundamental mechanism governing the magnetotransport properties shown by the compounds is then discussed.
2001 Academic Press
II. EXPERIMENTAL
La
\V Sr V CoO (x"0, 0.25, 0.5) samples were prepared in the form of sintered pellets following a classical method of 208