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<p>An attempt has been made here to synthesize K<sub>2</sub>NiF<sub>4</sub>-type Sr<sub>2</sub>(Ce<sub>1-y</sub>Ti<sub>y</sub>)O<sub>4</sub> (y = 0–1.0) oxides and characterise them with regard to structure, bond length/angles, Raman spectra, and electric characteristics. It exhibits an orthorhombic to tetragonal structural transformation with titanium. Both average cell volume and bond length decrease as ~ 228.21–190.06 Å<sup>3</sup> and ~ 2.715–2.311&#xa0;Å, respectively with titanium. Raman modes at ~ 287 and 385&#xa0;cm<sup>−1</sup> correspond to Ce–O<sub>2</sub> and Ce–O<sub>1</sub> bond stretching, respectively for y = 0 composition. The modes at ~ 122 and 204&#xa0;cm<sup>−1</sup> are associated with strontium ion vibrations, while those at ~ 284 and 575&#xa0;cm<sup>−1</sup> correspond to oxygen ion vibrations. Bands ~ 413 and 756&#xa0;cm<sup>−1</sup> are attributed to second-order bands or oxygen sublattice defects. Particularly, full with half maxima (FWHM) of the mode at 553&#xa0;cm<sup>−1</sup> decreases with titanium content—attributed to the reduction in degree of distortion of (Ce/Ti)O<sub>6</sub> octahedra. An absorption band at ~ 860&#xa0;cm<sup>−1</sup> is assigned to Ti–O bond stretching in TiO<sub>6</sub> octahedra for Sr<sub>2</sub>TiO<sub>4</sub>. The highest dielectric constant is found to be ~ 44.76 at 100&#xa0;kHz frequency for y = 1. The dielectric loss decreases as 4 × 10<sup>–3</sup>–2 × 10<sup>–3</sup> at a frequency of 100&#xa0;kHz with titanium. Dielectric anomaly is observed at higher temperature, associated with the space charge and defects related to oxygen vacancies. The activation energies have been calculated as ~ 0.84–0.95&#xa0;eV and increase with titanium. These characteristics make materials applications in high-frequency device applications e.g., 5G communication technology and antenna.</p>

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Effect of titanium substitution in Ruddlesden Popper‑type Sr2(Ce1-yTiy)O4 (y = 0–1.0) oxides: structural, optical and electrical investigations

  • 期刊论文

  • 发表日期：

    2025年12月16日

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  • Parvendra Kumar,
  • Shivendra Kumar Jaiswal

摘要

An attempt has been made here to synthesize K2NiF4-type Sr2(Ce1-yTiy)O4 (y = 0–1.0) oxides and characterise them with regard to structure, bond length/angles, Raman spectra, and electric characteristics. It exhibits an orthorhombic to tetragonal structural transformation with titanium. Both average cell volume and bond length decrease as ~ 228.21–190.06 Å3 and ~ 2.715–2.311 Å, respectively with titanium. Raman modes at ~ 287 and 385 cm−1 correspond to Ce–O2 and Ce–O1 bond stretching, respectively for y = 0 composition. The modes at ~ 122 and 204 cm−1 are associated with strontium ion vibrations, while those at ~ 284 and 575 cm−1 correspond to oxygen ion vibrations. Bands ~ 413 and 756 cm−1 are attributed to second-order bands or oxygen sublattice defects. Particularly, full with half maxima (FWHM) of the mode at 553 cm−1 decreases with titanium content—attributed to the reduction in degree of distortion of (Ce/Ti)O6 octahedra. An absorption band at ~ 860 cm−1 is assigned to Ti–O bond stretching in TiO6 octahedra for Sr2TiO4. The highest dielectric constant is found to be ~ 44.76 at 100 kHz frequency for y = 1. The dielectric loss decreases as 4 × 10–3–2 × 10–3 at a frequency of 100 kHz with titanium. Dielectric anomaly is observed at higher temperature, associated with the space charge and defects related to oxygen vacancies. The activation energies have been calculated as ~ 0.84–0.95 eV and increase with titanium. These characteristics make materials applications in high-frequency device applications e.g., 5G communication technology and antenna.