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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.


Electrical conductivity and Seebeck coefficient for  (solid symbol) and La1−xSrxMnO3±δ (open symbol) at R.T. [7]. The data of La1−xSrxCoO3±δ are reproduced by permission of The Royal Society of Chemistry.
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Figure 5: Electrical conductivity and Seebeck coefficient for (solid symbol) and La1−xSrxMnO3±δ (open symbol) at R.T. [7]. The data of La1−xSrxCoO3±δ are reproduced by permission of The Royal Society of Chemistry.

Mentions: The electrical conductivity (σ) and the Seebeck coefficient (S) of La1−xSrxCoO3±δ at R.T. as a function of the Sr concentration are shown in figure 5; neither has a relation with the lattice parameters. The σ value increased four orders of magnitude as the Sr concentration increased in the range of 0 ≤ x < 0.20 and then continued to increase gradually in the range of 0.20 ≤ x ≤ 0.50. The maximum conductivity of 4.4 × 103 S cm−1 was observed at x = 0.50. In the x > 0.50 concentration range, the σ value remained high until x = 0.80 and then decreased steeply for x > 0.80. This decrease in conductivity in the x > 0.80 range is attributed to the partial formation of a brownmillerite impurity phase. Overall, for the 0.20 ≤ x ≤ 0.80 range, the σ value was nearly independent of the Sr concentration. Such insensitivity to the composition ratio is an advantage for industrial applications.


Electronic conduction in La-based perovskite-type oxides
Electrical conductivity and Seebeck coefficient for  (solid symbol) and La1−xSrxMnO3±δ (open symbol) at R.T. [7]. The data of La1−xSrxCoO3±δ are reproduced 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 5: Electrical conductivity and Seebeck coefficient for (solid symbol) and La1−xSrxMnO3±δ (open symbol) at R.T. [7]. The data of La1−xSrxCoO3±δ are reproduced by permission of The Royal Society of Chemistry.
Mentions: The electrical conductivity (σ) and the Seebeck coefficient (S) of La1−xSrxCoO3±δ at R.T. as a function of the Sr concentration are shown in figure 5; neither has a relation with the lattice parameters. The σ value increased four orders of magnitude as the Sr concentration increased in the range of 0 ≤ x < 0.20 and then continued to increase gradually in the range of 0.20 ≤ x ≤ 0.50. The maximum conductivity of 4.4 × 103 S cm−1 was observed at x = 0.50. In the x > 0.50 concentration range, the σ value remained high until x = 0.80 and then decreased steeply for x > 0.80. This decrease in conductivity in the x > 0.80 range is attributed to the partial formation of a brownmillerite impurity phase. Overall, for the 0.20 ≤ x ≤ 0.80 range, the σ value was nearly independent of the Sr concentration. Such insensitivity to the composition ratio is an advantage for industrial applications.

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.