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Author: search.filters.author.Vittayakorn, WanwilaiSubject: search.filters.subject.Lepidocrocite titanate

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    Item type:Publication,
    Interlayer alkali ion governs robustness, reactivity, and dielectric properties of sintered lepidocrocite titanate
    (2022-01-01)
    Maluangnont, Tosapol
    ;
    Pulphol, Phieraya
    ;
    Vittayakorn, Wanwilai
    We investigate the structure across different length scales including the dielectric properties of Cs<inf>0.7</inf>Zn<inf>0.35</inf>Ti<inf>1.65</inf>O<inf>4</inf>, Rb<inf>0.75</inf>Zn<inf>0.375</inf>Ti<inf>1.625</inf>O<inf>4</inf>, and K<inf>0.8</inf>Zn<inf>0.4</inf>Ti<inf>1.6</inf>O<inf>4</inf> sintered at T<inf>S</inf> ​= ​900–1100 ​°C, where the lepidocrocite-type crystal structure is preserved. The increasing interlayer distance in the Rb-/K-analog is explained by the alkali loss which reduces the electrostatic attraction between the sheets and the interlayer ion. Meanwhile, the interlayer contraction in the Cs-analog is rather unusual. The increasing (decreasing) interlayer distances correlate to upshift (downshift) of the Ti-O vibration in the Raman spectra. The three compositions show varied grain orientation depending on the interlayer ion and T<inf>S</inf>. The dielectric permittivity differs by one order of magnitude in the order Cs<inf>0.7</inf>Zn<inf>0.35</inf>Ti<inf>1.65</inf>O<inf>4</inf> « Rb<inf>0.75</inf>Zn<inf>0.375</inf>Ti<inf>1.625</inf>O<inf>4</inf> « K<inf>0.8</inf>Zn<inf>0.4</inf>Ti<inf>1.6</inf>O<inf>4</inf>, suggesting the interlayer ion as the dominating dipole. The influences of T<inf>S</inf>, pellet density (i.e., alkali loss), and grain size/morphology/orientation on the dielectric permittivity are discussed. The understanding of the response to a high temperature treatment would be beneficial not only to specimen fabrications for physical properties measurements, but also to applications where the thermal stability is of concern.