High electrical conductivity of layered cobalt oxide Ca_3Co_4O_9 epitaxial films grown by topotactic ion-exchange method
抄録
Epitaxial film of a layered cobalt oxide, Ca_3Co_4O_9, was fabricated on a (0001) face of an α-Al_2O_3 substrate by a topotactic ion-exchange method using a γ-Na_0.8CoO_2 epitaxial film as a precursor. High-resolution x-ray diffraction and atomic force microscope measurements revealed that the film was high-quality (001)-oriented Ca_3Co_4O_9 with stepped and terraced surface morphology. The film exhibits a high electrical conductivity of 2.95*10^2 S cm^-1 and a large Seebeck coefficient of ～ +125 μVK^-1, which leads to the thermoelectric power factor (TPF) of 4.5*10^-4 Wm^-1 K^-2 at 300 K, potentially usable as a building block of the multilayered film structure with an enhanced TPF value.
収録刊行物
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- Applied Physics Letters
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Applied Physics Letters 89 (3), 032111-032111, 2006-01-17
American Institute of Physics