کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1525361 995354 2010 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Electrical conductivity, Seebeck coefficient, and defect structure of oxygen nonstoichiometric Nd2−xSrxNiO4+δ
موضوعات مرتبط
مهندسی و علوم پایه مهندسی مواد مواد الکترونیکی، نوری و مغناطیسی
پیش نمایش صفحه اول مقاله
Electrical conductivity, Seebeck coefficient, and defect structure of oxygen nonstoichiometric Nd2−xSrxNiO4+δ
چکیده انگلیسی

To elucidate the electronic state and the conduction mechanism of Nd2NiO4+δ series oxides at high temperatures, the electrical conductivity, Seebeck coefficient, and nonstoichiometric oxygen content of Nd2−xSrxNiO4+δ (x = 0, 0.2, 0.4) were measured as a function of the Sr content, temperature, and oxygen partial pressure. The hole mobility is estimated from the electrical conductivity and the hole concentration which is defect chemically determined. The mobility slightly decreases as temperature increases as in metals at high temperatures. The relationships between the Seebeck coefficient, electrical conductivity, and hole concentration can be explained by Mott's equation, which expresses the Seebeck coefficient for metals. Semi-quantitative analyses strongly indicate that the electron or hole is itinerant in Nd2−xSrxNiO4+δ, and the conduction mechanism is metal-like band conduction at high temperatures. Based on the experimental results, schematics for energy level and band structure are proposed. At high temperatures, free holes in the σx2−y2 band composed of dx2−y2 orbitals contribute to metallic conduction.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Materials Chemistry and Physics - Volume 122, Issue 1, 1 July 2010, Pages 250–258
نویسندگان
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