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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.


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(a) Temperature dependence of the electrical conductivity, σ, for La1−xSrxMnO3±δ (0 ≤ x ≤ 1.0) and (b) enlarged view with a linear scale for σ ≤ 1000 S cm−1. Reproduced from [9] by permission of The Royal Society of Chemistry.
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Figure 9: (a) Temperature dependence of the electrical conductivity, σ, for La1−xSrxMnO3±δ (0 ≤ x ≤ 1.0) and (b) enlarged view with a linear scale for σ ≤ 1000 S cm−1. Reproduced from [9] by permission of The Royal Society of Chemistry.

Mentions: Figure 9 shows the σ values for La1−xSrxMnO3±δ measured between R.T. and 1073 K for various Sr concentrations. The largest value of σ was observed between 423 and 1073 K when x = 0.67, but samples with 0.33 ≤ x ≤ 0.80 also exhibited high σ values. On the other hand, the largest value of σ at 300–423 K was obtained when x = 0.40. In addition, the σ values for x = 0.33, 0.40 and 0.50 exhibited metallic behavior over the entire temperature range, i.e. σ decreased as the temperature increased, except for an anomaly that occurred between 373–473 K. This anomaly is due to a ferromagnetic to paramagnetic transition [62]. In contrast, the σ values for x = 0.55, 0.67 and 0.80 exhibited a metal–insulator transition at approximately 373 K (semiconducting behavior appeared at T < 373 K, whereas metallic behavior was observed at T ≥ 373 K). In addition, the temperature of the metal–insulator transition increased as the Sr content increased. Consequently, both the largest σ value between 423 K and 1073 K and the lowest rate of the change of the σ value with the temperature were observed when x = 0.67, which is therefore a suitable composition for use as oxide electrodes and wiring that are operated at high temperatures in air.


Electronic conduction in La-based perovskite-type oxides
(a) Temperature dependence of the electrical conductivity, σ, for La1−xSrxMnO3±δ (0 ≤ x ≤ 1.0) and (b) enlarged view with a linear scale for σ ≤ 1000 S cm−1. Reproduced from [9] 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 9: (a) Temperature dependence of the electrical conductivity, σ, for La1−xSrxMnO3±δ (0 ≤ x ≤ 1.0) and (b) enlarged view with a linear scale for σ ≤ 1000 S cm−1. Reproduced from [9] by permission of The Royal Society of Chemistry.
Mentions: Figure 9 shows the σ values for La1−xSrxMnO3±δ measured between R.T. and 1073 K for various Sr concentrations. The largest value of σ was observed between 423 and 1073 K when x = 0.67, but samples with 0.33 ≤ x ≤ 0.80 also exhibited high σ values. On the other hand, the largest value of σ at 300–423 K was obtained when x = 0.40. In addition, the σ values for x = 0.33, 0.40 and 0.50 exhibited metallic behavior over the entire temperature range, i.e. σ decreased as the temperature increased, except for an anomaly that occurred between 373–473 K. This anomaly is due to a ferromagnetic to paramagnetic transition [62]. In contrast, the σ values for x = 0.55, 0.67 and 0.80 exhibited a metal–insulator transition at approximately 373 K (semiconducting behavior appeared at T < 373 K, whereas metallic behavior was observed at T ≥ 373 K). In addition, the temperature of the metal–insulator transition increased as the Sr content increased. Consequently, both the largest σ value between 423 K and 1073 K and the lowest rate of the change of the σ value with the temperature were observed when x = 0.67, which is therefore a suitable composition for use as oxide electrodes and wiring that are operated at high temperatures in air.

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.


Related in: MedlinePlus