Preparation, crystal structure and thermoelectric properties of la 2-2xCa1+2xMn2O7

Yuzuru Miyazaki, Daisuke Abe, Tsuyoshi Kajitani

Research output: Chapter in Book/Report/Conference proceedingConference contribution

4 Citations (Scopus)

Abstract

We have prepared polycrystalline samples of the Ruddlesden-Popper La 2-2xCa1+2xMn2O7 phase and determined their crystal structure and thermoelectric properties above room temperature. Single-phase samples with tetragonal I4/mmm space group are obtained for the samples with 0.50 ≤ x ≤ 1.00; the corresponding valence state of Mn is from 3.5 to 4.0. With increasing x, the a-axis length gradually decreases from 3.8268(4) Å (x = 0.5) to 3.7078(2) Å (x = 1.0), while the c-axis length increases from 19.197(3) Å (x = 0.5) to 19.438(1) Å (x = 1.0). As expected, all the samples exhibit negative Seebeck coefficients, S. The absolute value of S increases with increasing x, and the phases become electrically conductive at high temperatures. For example, the sample with x = 0.50 exhibits the electrical conductivity, σ = 35 S/cm and S = -40μV/K at 1123 K, compared with those of the sample with x = 0.95 of σ= 18 S/cm and S = -175 μV/K. The highest ZT ∼0.03 with the power factor of 5.5 × 10-5 W/mK2, has been obtained for the x = 0.95 sample at 1123 K.

Original languageEnglish
Title of host publicationProceedings ICT'07 - 26th International Conference on Thermoelectrics
Pages129-132
Number of pages4
DOIs
Publication statusPublished - 2007 Dec 1
EventICT'07 - 26th International Conference on Thermoelectrics - Jeju, Korea, Republic of
Duration: 2007 Jun 32007 Jun 7

Publication series

NameInternational Conference on Thermoelectrics, ICT, Proceedings

Other

OtherICT'07 - 26th International Conference on Thermoelectrics
Country/TerritoryKorea, Republic of
CityJeju
Period07/6/307/6/7

ASJC Scopus subject areas

  • Engineering(all)

Fingerprint

Dive into the research topics of 'Preparation, crystal structure and thermoelectric properties of la <sub>2-2x</sub>Ca<sub>1+2x</sub>Mn<sub>2</sub>O<sub>7</sub>'. Together they form a unique fingerprint.

Cite this