The effects of sintering temperature on preparation, resistivity, and thermopower of c-axis oriented Ca3Co3.95Fe0.05O9 + δ films fabricated using sol-gel spin coating method

Chia-Jyi Liu, Pradipta K. Nayak, Zhi Ru Lin, Kai Yi Jeng

Research output: Contribution to journalArticle

24 Citations (Scopus)

Abstract

We report fabrication of the c-axis oriented Ca3Co3.95Fe0.05O9 + δ films by a simple sol-gel spin coating method. The films prepared in the temperature range of 650-700 °C show nonmetallic temperature dependence of resistivity in the whole investigated temperature range, whereas the films prepared in the temperature range of 750-775 °C show metallic temperature dependence in the high temperature regime. Sintering the films at higher temperature leads to larger grains, lower resistivity and smaller thermoelectric power. This can be explained in the framework of the barrier theory and confirmed by the higher hole carrier concentration from the Hall measurements according to Seto's derivation between the carrier concentration and the barrier height. The temperature dependence of resistivity resembles that of the in-plane single crystal of Ca3Co4O9 + δ in terms of the Fermi-liquid behavior. The effects of lower sintering temperature on the transport coefficient A and Fermi-liquid scale T* of Fe-substituted cobaltite films seems to be similar to applying hydrostatic pressure on a single crystal of Ca3Co4O9 + δ. The temperature dependence of resistivity in the nonmetallic region follows the variable-range hopping conduction in the form of T- 1/3, due to the 2-dimensional character of the films.

Original languageEnglish
Pages (from-to)8564-8568
Number of pages5
JournalThin Solid Films
Volume516
Issue number23
DOIs
Publication statusPublished - 2008 Oct 1

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Thermoelectric power
Spin coating
Sol-gels
coating
sintering
Sintering
gels
preparation
electrical resistivity
temperature dependence
Fermi liquids
Temperature
temperature
single crystals
Carrier concentration
hydrostatic pressure
Single crystals
derivation
transport properties
conduction

All Science Journal Classification (ASJC) codes

  • Surfaces, Coatings and Films
  • Condensed Matter Physics
  • Surfaces and Interfaces

Cite this

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title = "The effects of sintering temperature on preparation, resistivity, and thermopower of c-axis oriented Ca3Co3.95Fe0.05O9 + δ films fabricated using sol-gel spin coating method",
abstract = "We report fabrication of the c-axis oriented Ca3Co3.95Fe0.05O9 + δ films by a simple sol-gel spin coating method. The films prepared in the temperature range of 650-700 °C show nonmetallic temperature dependence of resistivity in the whole investigated temperature range, whereas the films prepared in the temperature range of 750-775 °C show metallic temperature dependence in the high temperature regime. Sintering the films at higher temperature leads to larger grains, lower resistivity and smaller thermoelectric power. This can be explained in the framework of the barrier theory and confirmed by the higher hole carrier concentration from the Hall measurements according to Seto's derivation between the carrier concentration and the barrier height. The temperature dependence of resistivity resembles that of the in-plane single crystal of Ca3Co4O9 + δ in terms of the Fermi-liquid behavior. The effects of lower sintering temperature on the transport coefficient A and Fermi-liquid scale T* of Fe-substituted cobaltite films seems to be similar to applying hydrostatic pressure on a single crystal of Ca3Co4O9 + δ. The temperature dependence of resistivity in the nonmetallic region follows the variable-range hopping conduction in the form of T- 1/3, due to the 2-dimensional character of the films.",
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The effects of sintering temperature on preparation, resistivity, and thermopower of c-axis oriented Ca3Co3.95Fe0.05O9 + δ films fabricated using sol-gel spin coating method. / Liu, Chia-Jyi; Nayak, Pradipta K.; Lin, Zhi Ru; Jeng, Kai Yi.

In: Thin Solid Films, Vol. 516, No. 23, 01.10.2008, p. 8564-8568.

Research output: Contribution to journalArticle

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AU - Liu, Chia-Jyi

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AU - Lin, Zhi Ru

AU - Jeng, Kai Yi

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AB - We report fabrication of the c-axis oriented Ca3Co3.95Fe0.05O9 + δ films by a simple sol-gel spin coating method. The films prepared in the temperature range of 650-700 °C show nonmetallic temperature dependence of resistivity in the whole investigated temperature range, whereas the films prepared in the temperature range of 750-775 °C show metallic temperature dependence in the high temperature regime. Sintering the films at higher temperature leads to larger grains, lower resistivity and smaller thermoelectric power. This can be explained in the framework of the barrier theory and confirmed by the higher hole carrier concentration from the Hall measurements according to Seto's derivation between the carrier concentration and the barrier height. The temperature dependence of resistivity resembles that of the in-plane single crystal of Ca3Co4O9 + δ in terms of the Fermi-liquid behavior. The effects of lower sintering temperature on the transport coefficient A and Fermi-liquid scale T* of Fe-substituted cobaltite films seems to be similar to applying hydrostatic pressure on a single crystal of Ca3Co4O9 + δ. The temperature dependence of resistivity in the nonmetallic region follows the variable-range hopping conduction in the form of T- 1/3, due to the 2-dimensional character of the films.

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