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Electronic conduction in La-based perovskite-type oxides

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ABSTRACT

A systematic study of La-based perovskite-type oxides from the viewpoint of their electronic conduction properties was performed. LaCo0.5Ni0.5O3±δ was found to be a promising candidate as a replacement for standard metals used in oxide electrodes and wiring that are operated at temperatures up to 1173 K in air because of its high electrical conductivity and stability at high temperatures. LaCo0.5Ni0.5O3±δ exhibits a high conductivity of 1.9 × 103 S cm−1 at room temperature (R.T.) because of a high carrier concentration n of 2.2 × 1022 cm−3 and a small effective mass m∗ of 0.10 me. Notably, LaCo0.5Ni0.5O3±δ exhibits this high electrical conductivity from R.T. to 1173 K, and little change in the oxygen content occurs under these conditions. LaCo0.5Ni0.5O3±δ is the most suitable for the fabrication of oxide electrodes and wiring, though La1−xSrxCoO3±δ and La1−xSrxMnO3±δ also exhibit high electronic conductivity at R.T., with maximum electrical conductivities of 4.4 × 103 S cm−1 for La0.5Sr0.5CoO3±δ and 1.5 × 103 S cm−1 for La0.6Sr0.4MnO3±δ because oxygen release occurs in La1−xSrxCoO3±δ as elevating temperature and the electrical conductivity of La0.6Sr0.4MnO3±δ slightly decreases at temperatures above 400 K.

No MeSH data available.


Carrier concentration, mobility, effective mass and relaxation time for La1−xSrxCoO3±δ at R.T. The dotted line indicates the theoretical value of the carrier concentration. Reproduced from [7] by permission of The Royal Society of Chemistry.
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Figure 6: Carrier concentration, mobility, effective mass and relaxation time for La1−xSrxCoO3±δ at R.T. The dotted line indicates the theoretical value of the carrier concentration. Reproduced from [7] by permission of The Royal Society of Chemistry.

Mentions: The p–n transition between x = 0 and 0.05 was also observed during Hall-effect measurements. The Hall coefficient reversed from negative to positive between x = 0 and 0.05. This result agrees with the behavior of S. This transition is caused by the increase in hole concentration by Sr doping to the La-site. Figure 6 shows the carrier concentration (n) and the carrier mobility (μ) for La1−xSrxCoO3±δ at R.T. The n value increased two orders of magnitude as the Sr concentration increased in the range of 0 ≤ x ≤ 0.36 and reached a maximum of 8.4 × 1021 cm−3. According to equation (2) (Kröger–Vink notation), the n value should continue to increase with the increasing Sr concentration if Sr is completely substituted into the La-sites with additional oxygen incorporation. This theoretical curve for n is shown as the dotted line in figure 6. The theoretical value was calculated using the Sr concentration and lattice volume because the hole concentration [h·] is equal to the Sr concentration [Sr′La] when the above condition is satisfied2


Electronic conduction in La-based perovskite-type oxides
Carrier concentration, mobility, effective mass and relaxation time for La1−xSrxCoO3±δ at R.T. The dotted line indicates the theoretical value of the carrier concentration. Reproduced from [7] by permission of The Royal Society of Chemistry.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC5036473&req=5

Figure 6: Carrier concentration, mobility, effective mass and relaxation time for La1−xSrxCoO3±δ at R.T. The dotted line indicates the theoretical value of the carrier concentration. Reproduced from [7] by permission of The Royal Society of Chemistry.
Mentions: The p–n transition between x = 0 and 0.05 was also observed during Hall-effect measurements. The Hall coefficient reversed from negative to positive between x = 0 and 0.05. This result agrees with the behavior of S. This transition is caused by the increase in hole concentration by Sr doping to the La-site. Figure 6 shows the carrier concentration (n) and the carrier mobility (μ) for La1−xSrxCoO3±δ at R.T. The n value increased two orders of magnitude as the Sr concentration increased in the range of 0 ≤ x ≤ 0.36 and reached a maximum of 8.4 × 1021 cm−3. According to equation (2) (Kröger–Vink notation), the n value should continue to increase with the increasing Sr concentration if Sr is completely substituted into the La-sites with additional oxygen incorporation. This theoretical curve for n is shown as the dotted line in figure 6. The theoretical value was calculated using the Sr concentration and lattice volume because the hole concentration [h·] is equal to the Sr concentration [Sr′La] when the above condition is satisfied2

View Article: PubMed Central - PubMed

ABSTRACT

A systematic study of La-based perovskite-type oxides from the viewpoint of their electronic conduction properties was performed. LaCo0.5Ni0.5O3±δ was found to be a promising candidate as a replacement for standard metals used in oxide electrodes and wiring that are operated at temperatures up to 1173 K in air because of its high electrical conductivity and stability at high temperatures. LaCo0.5Ni0.5O3±δ exhibits a high conductivity of 1.9 × 103 S cm−1 at room temperature (R.T.) because of a high carrier concentration n of 2.2 × 1022 cm−3 and a small effective mass m∗ of 0.10 me. Notably, LaCo0.5Ni0.5O3±δ exhibits this high electrical conductivity from R.T. to 1173 K, and little change in the oxygen content occurs under these conditions. LaCo0.5Ni0.5O3±δ is the most suitable for the fabrication of oxide electrodes and wiring, though La1−xSrxCoO3±δ and La1−xSrxMnO3±δ also exhibit high electronic conductivity at R.T., with maximum electrical conductivities of 4.4 × 103 S cm−1 for La0.5Sr0.5CoO3±δ and 1.5 × 103 S cm−1 for La0.6Sr0.4MnO3±δ because oxygen release occurs in La1−xSrxCoO3±δ as elevating temperature and the electrical conductivity of La0.6Sr0.4MnO3±δ slightly decreases at temperatures above 400 K.

No MeSH data available.