Site-selective doping of transition metal cations into NaCo2O4

Yoshihiro Nojiri, Michitaka Ohtaki

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

    3 Citations (Scopus)

    Abstract

    We have investigated site-selective doping of Ni in order to experimentally explore the roles of the Na and Co sites of NaCO2O4. The selective doping is carried out by changing preparation procedures of the oxide. Cation "substitution" is intended by incorporating Ni(NO3)2 into a Co-deficient starting mixture of Na2CO3 and Co3O4 prior to the first heat treatment. Cation "exchange" is, on the other hand, carried out by heating a mixture of Ni(NO3), and a single phase sample ofNaCo2O4, which has been prepared beforehand from a stoichiometric starting mixture. Comparison with control samples without addition of Ni(NO3)2 reveals that the "substituted" sample shows a significant decrease in the thermo power with keeping the electrical conductivity almost intact, while the "exchanged" sample shows the lower electrical conductivity with leaving the thermo power unchanged. These results strongly suggest that Ni cations occupy different sites in the Ni-doped samples; disturbing Co-Co spin exchange at the Co site, and compensating holes at the Na site.

    Original languageEnglish
    Title of host publicationProceedings ICT 2002: 21st International Conference on Thermoelectrics
    PublisherInstitute of Electrical and Electronics Engineers Inc.
    Pages234-237
    Number of pages4
    Volume2002-January
    ISBN (Electronic)0780376838
    DOIs
    Publication statusPublished - 2002
    Event21st International Conference on Thermoelectrics, ICT 2002 - Long Beach, United States
    Duration: Aug 25 2002Aug 29 2002

    Other

    Other21st International Conference on Thermoelectrics, ICT 2002
    CountryUnited States
    CityLong Beach
    Period8/25/028/29/02

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    All Science Journal Classification (ASJC) codes

    • Condensed Matter Physics
    • Electrical and Electronic Engineering

    Cite this

    Nojiri, Y., & Ohtaki, M. (2002). Site-selective doping of transition metal cations into NaCo2O4 In Proceedings ICT 2002: 21st International Conference on Thermoelectrics (Vol. 2002-January, pp. 234-237). [1190308] Institute of Electrical and Electronics Engineers Inc.. https://doi.org/10.1109/ICT.2002.1190308