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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, n, carrier mobility, μ, effective mass, m∗, and relaxation time, τ, for LaCo1−xNixO3±δ at R.T. The solid line indicates the theoretical value of the carrier concentration. Reprinted with permission from [8]. Copyright © 2012 American Chemical Society.
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Figure 14: Carrier concentration, n, carrier mobility, μ, effective mass, m∗, and relaxation time, τ, for LaCo1−xNixO3±δ at R.T. The solid line indicates the theoretical value of the carrier concentration. Reprinted with permission from [8]. Copyright © 2012 American Chemical Society.

Mentions: The carrier concentration (n) and the mobility (μ) were also discontinuous between 0.20 < x < 0.30, as shown in figure 14. The Hall coefficient was reversed from negative to positive for 0 < x < 0.05, indicating that LaCo1−xNixO3±δ (0.05 ≤ x ≤ 0.50) is a p-type conductor and that LaCoO3 is an n-type conductor. This p–n transition is caused by the increase in hole concentration by Ni doping to the Co-site according to equation (10). The n value increased as x increased and reached a maximum of 2.2 × 1022 cm−3 at x = 0.50, which is extremely high for oxides. For 0 ≤ x ≤ 0.20, the observed values of n were less than the theoretical values, which are indicated in figure 14 by the solid line. The oxygen content for x = 0.20 was calculated using equations (4) and (10), and the difference in the observed and theoretical values was 2.9310


Electronic conduction in La-based perovskite-type oxides
Carrier concentration, n, carrier mobility, μ, effective mass, m∗, and relaxation time, τ, for LaCo1−xNixO3±δ at R.T. The solid line indicates the theoretical value of the carrier concentration. Reprinted with permission from [8]. Copyright © 2012 American Chemical Society.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 14: Carrier concentration, n, carrier mobility, μ, effective mass, m∗, and relaxation time, τ, for LaCo1−xNixO3±δ at R.T. The solid line indicates the theoretical value of the carrier concentration. Reprinted with permission from [8]. Copyright © 2012 American Chemical Society.
Mentions: The carrier concentration (n) and the mobility (μ) were also discontinuous between 0.20 < x < 0.30, as shown in figure 14. The Hall coefficient was reversed from negative to positive for 0 < x < 0.05, indicating that LaCo1−xNixO3±δ (0.05 ≤ x ≤ 0.50) is a p-type conductor and that LaCoO3 is an n-type conductor. This p–n transition is caused by the increase in hole concentration by Ni doping to the Co-site according to equation (10). The n value increased as x increased and reached a maximum of 2.2 × 1022 cm−3 at x = 0.50, which is extremely high for oxides. For 0 ≤ x ≤ 0.20, the observed values of n were less than the theoretical values, which are indicated in figure 14 by the solid line. The oxygen content for x = 0.20 was calculated using equations (4) and (10), and the difference in the observed and theoretical values was 2.9310

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&plusmn;&delta; 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&plusmn;&delta; exhibits a high conductivity of 1.9 &times; 103 S cm&minus;1 at room temperature (R.T.) because of a high carrier concentration n of 2.2 &times; 1022 cm&minus;3 and a small effective mass m&lowast; of 0.10 me. Notably, LaCo0.5Ni0.5O3&plusmn;&delta; 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&plusmn;&delta; is the most suitable for the fabrication of oxide electrodes and wiring, though La1&minus;xSrxCoO3&plusmn;&delta; and La1&minus;xSrxMnO3&plusmn;&delta; also exhibit high electronic conductivity at R.T., with maximum electrical conductivities of 4.4 &times; 103 S cm&minus;1 for La0.5Sr0.5CoO3&plusmn;&delta; and 1.5 &times; 103 S cm&minus;1 for La0.6Sr0.4MnO3&plusmn;&delta; because oxygen release occurs in La1&minus;xSrxCoO3&plusmn;&delta; as elevating temperature and the electrical conductivity of La0.6Sr0.4MnO3&plusmn;&delta; slightly decreases at temperatures above 400 K.

No MeSH data available.