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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 of La1−xAExCoO3 at R.T. Reproduced from [6] by permission of The Royal Society of Chemistry.
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Figure 2: Electrical conductivity of La1−xAExCoO3 at R.T. Reproduced from [6] by permission of The Royal Society of Chemistry.

Mentions: The electrical conductivity (σ) for the Sr-doped material was the highest among the oxides doped with the three different AE elements when x ≥ 0.25. Notably, the Co–O bond lengths were also the shortest in this composition range. These results suggested a relation between σ and the Co–O bond length. Figure 2 shows the AE concentration dependence of the σ values obtained at R.T. for 0 ≤ x ≤ 0.40. In the 0 ≤ x ≤ 0.20 range, the σ value increased four orders of magnitude as the AE concentration increased, although there was no significant change in σ as a function of the ionic radius of the AE element. On the other hand, the highest values of σ for the Sr-doped system were observed when 0.20 < x ≤ 0.40, with a maximum of 4.4 × 103 S cm−1 reached at x = 0.40. This value is the highest level compared with any previously reported value [18, 25]. The conductivities for the Ca- and Ba-doped materials, however, reached maximum values of 1.9 × 103 S cm−1 at x = 0.25 and 2.7 × 103 S cm−1 at x = 0.30, respectively. Notably, these materials are potential replacements for metal electrodes and wiring.


Electronic conduction in La-based perovskite-type oxides
Electrical conductivity of La1−xAExCoO3 at R.T. Reproduced from [6] 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 2: Electrical conductivity of La1−xAExCoO3 at R.T. Reproduced from [6] by permission of The Royal Society of Chemistry.
Mentions: The electrical conductivity (σ) for the Sr-doped material was the highest among the oxides doped with the three different AE elements when x ≥ 0.25. Notably, the Co–O bond lengths were also the shortest in this composition range. These results suggested a relation between σ and the Co–O bond length. Figure 2 shows the AE concentration dependence of the σ values obtained at R.T. for 0 ≤ x ≤ 0.40. In the 0 ≤ x ≤ 0.20 range, the σ value increased four orders of magnitude as the AE concentration increased, although there was no significant change in σ as a function of the ionic radius of the AE element. On the other hand, the highest values of σ for the Sr-doped system were observed when 0.20 < x ≤ 0.40, with a maximum of 4.4 × 103 S cm−1 reached at x = 0.40. This value is the highest level compared with any previously reported value [18, 25]. The conductivities for the Ca- and Ba-doped materials, however, reached maximum values of 1.9 × 103 S cm−1 at x = 0.25 and 2.7 × 103 S cm−1 at x = 0.30, respectively. Notably, these materials are potential replacements for metal electrodes and wiring.

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.