کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
10576823 | 979100 | 2005 | 6 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Sr2/3Y1/3CoO8/3+δ: Transition from insulating antiferromagnet to metallic ferromagnet by control of the oxygen content
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی معدنی
پیش نمایش صفحه اول مقاله
![عکس صفحه اول مقاله: Sr2/3Y1/3CoO8/3+δ: Transition from insulating antiferromagnet to metallic ferromagnet by control of the oxygen content Sr2/3Y1/3CoO8/3+δ: Transition from insulating antiferromagnet to metallic ferromagnet by control of the oxygen content](/preview/png/10576823.png)
چکیده انگلیسی
Magnetic and electronic properties of the oxygen deficient ordered perovskite, Sr2/3Y1/3CoO8/3+δ, have been studied for two different oxygen contents corresponding to δ=0.00 and 0.04 in the chemical formula. For the former, at low temperature, the background state is antiferromagnetic insulating (TN=290K,Ï10K=4Ã105Ωcm) as expected from the presence of trivalent cobalt in the high spin-state. Remarkably, the more oxidized compound with a cobalt oxidation state of â3.08 is a ferromagnetic half-metal with TC=225KandÏ10K=2Ã10-3Ωcm. Consistently, upon application of an external magnetic field, the spin-scattering reduction in the TC vicinity is responsible for a weak negative magnetoresistance. These dramatic changes of the physical properties for such a slight increase of the cobalt oxidation state are interpreted as a result of the structural disordering created by the extra oxygens. The thermoelectric power measurements, showing a sign change of the Seebeck coefficient as the oxygen content increases, indicate that electrons moving in a metallic eg band dominate the transport properties of the ferromagnetic and metallic compound. This suggests the existence of an orbital ordering in the pristine compound, related to an ordered array of CoO4 tetrahedra, which can be collapsed by the presence of these extra oxygen anions.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Solid State Chemistry - Volume 178, Issue 3, March 2005, Pages 868-873
Journal: Journal of Solid State Chemistry - Volume 178, Issue 3, March 2005, Pages 868-873
نویسندگان
A. Maignan, S. Hébert, V. Caignaert, V. Pralong, D. Pelloquin,