Epitaxially strained Na0.7CoO2 thin films on SrTiO3 buffer layer

J. Y. Son, Y. H. Shin, Hyungjun Kim

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

We prepared Na0.7CoO2 thin films on (0 0 1) Al2O3 substrates that showed a negligibly strained structure and a metallic behavior similar to Na0.7CoO2 single crystal. In particular, a Na0.7CoO2 thin film on a (1 1 1) SrTiO3/(0 0 1) Al2O3 substrate exhibited an elongated c-lattice constant as well as an anomaly in the electric transporting behavior: a transition from an insulating state to a metallic state at 105 K. This change is caused by the structural symmetry break near the cubic-to-tetragonal transition temperature of SrTiO3. From spectroscopic ellipsometry analysis, we obtained optical conductivities for the Na0.7CoO2 thin films on the Al2O3 and SrTiO3/Al2O3 substrates. The Na0.7CoO2 thin film on the SrTiO3/Al2O3 substrate exhibited higher energy splitting between eg and a1g than the Na0.7CoO2 thin film on the Al2O3 substrate, resulting from the c-lattice elongation.

Original languageEnglish
Pages (from-to)1021-1024
Number of pages4
JournalJournal of Crystal Growth
Volume311
Issue number4
DOIs
Publication statusPublished - 2009 Feb 1

Fingerprint

Buffer layers
buffers
Thin films
Substrates
thin films
Optical conductivity
Spectroscopic ellipsometry
Superconducting transition temperature
elongation
Lattice constants
ellipsometry
Elongation
transition temperature
strontium titanium oxide
Single crystals
anomalies
conductivity
single crystals
symmetry
energy

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics
  • Inorganic Chemistry
  • Materials Chemistry

Cite this

Son, J. Y. ; Shin, Y. H. ; Kim, Hyungjun. / Epitaxially strained Na0.7CoO2 thin films on SrTiO3 buffer layer. In: Journal of Crystal Growth. 2009 ; Vol. 311, No. 4. pp. 1021-1024.
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abstract = "We prepared Na0.7CoO2 thin films on (0 0 1) Al2O3 substrates that showed a negligibly strained structure and a metallic behavior similar to Na0.7CoO2 single crystal. In particular, a Na0.7CoO2 thin film on a (1 1 1) SrTiO3/(0 0 1) Al2O3 substrate exhibited an elongated c-lattice constant as well as an anomaly in the electric transporting behavior: a transition from an insulating state to a metallic state at 105 K. This change is caused by the structural symmetry break near the cubic-to-tetragonal transition temperature of SrTiO3. From spectroscopic ellipsometry analysis, we obtained optical conductivities for the Na0.7CoO2 thin films on the Al2O3 and SrTiO3/Al2O3 substrates. The Na0.7CoO2 thin film on the SrTiO3/Al2O3 substrate exhibited higher energy splitting between eg and a1g than the Na0.7CoO2 thin film on the Al2O3 substrate, resulting from the c-lattice elongation.",
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Epitaxially strained Na0.7CoO2 thin films on SrTiO3 buffer layer. / Son, J. Y.; Shin, Y. H.; Kim, Hyungjun.

In: Journal of Crystal Growth, Vol. 311, No. 4, 01.02.2009, p. 1021-1024.

Research output: Contribution to journalArticle

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AU - Son, J. Y.

AU - Shin, Y. H.

AU - Kim, Hyungjun

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N2 - We prepared Na0.7CoO2 thin films on (0 0 1) Al2O3 substrates that showed a negligibly strained structure and a metallic behavior similar to Na0.7CoO2 single crystal. In particular, a Na0.7CoO2 thin film on a (1 1 1) SrTiO3/(0 0 1) Al2O3 substrate exhibited an elongated c-lattice constant as well as an anomaly in the electric transporting behavior: a transition from an insulating state to a metallic state at 105 K. This change is caused by the structural symmetry break near the cubic-to-tetragonal transition temperature of SrTiO3. From spectroscopic ellipsometry analysis, we obtained optical conductivities for the Na0.7CoO2 thin films on the Al2O3 and SrTiO3/Al2O3 substrates. The Na0.7CoO2 thin film on the SrTiO3/Al2O3 substrate exhibited higher energy splitting between eg and a1g than the Na0.7CoO2 thin film on the Al2O3 substrate, resulting from the c-lattice elongation.

AB - We prepared Na0.7CoO2 thin films on (0 0 1) Al2O3 substrates that showed a negligibly strained structure and a metallic behavior similar to Na0.7CoO2 single crystal. In particular, a Na0.7CoO2 thin film on a (1 1 1) SrTiO3/(0 0 1) Al2O3 substrate exhibited an elongated c-lattice constant as well as an anomaly in the electric transporting behavior: a transition from an insulating state to a metallic state at 105 K. This change is caused by the structural symmetry break near the cubic-to-tetragonal transition temperature of SrTiO3. From spectroscopic ellipsometry analysis, we obtained optical conductivities for the Na0.7CoO2 thin films on the Al2O3 and SrTiO3/Al2O3 substrates. The Na0.7CoO2 thin film on the SrTiO3/Al2O3 substrate exhibited higher energy splitting between eg and a1g than the Na0.7CoO2 thin film on the Al2O3 substrate, resulting from the c-lattice elongation.

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