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<p>To support the advancement of layered perovskite ceramics for next-generation wireless and millimeter-wave communication technologies, a series of Sr<sub>2</sub>Sn<sub>1−x</sub>Ce<sub>x</sub>O<sub>4</sub> (x = 0, 0.10, 0.20, 0.30, 0.40, and 0.50) (SSC) were synthesized via the conventional solid-state reaction method, followed by calcination at 1100&#xa0;°C and sintering at 1300&#xa0;°C. Structural analysis through X-ray diffraction (XRD) confirmed the formation of a single-phase tetragonal crystal structure (space group <i>I4/mmm</i>) for compositions up to <i>x</i> = 0.20. Beyond this concentration, the emergence of a secondary Sr<sub>2</sub>CeO<sub>4</sub> phase indicated a solubility limit for Ce substitution at the Sn site between <i>x</i> = 0.20 and <i>x</i> = 0.30. This structural evolution was further corroborated by FTIR and Raman spectroscopy, which supported the phase transition and changes in local bonding environments. Microstructural examinations revealed that Ce doping significantly influenced grain morphology and agglomeration tendencies. The coexistence of oxygen vacancies, interstitials, and multivalent cations—namely Sn<sup>2+</sup>/Sn<sup>4+</sup> and Ce<sup>2+</sup>/Ce<sup>3+</sup>/Ce<sup>4+</sup> played a crucial role in modulating the electrical and microwave dielectric behavior. Dielectric properties were predominantly governed by orientational polarization mechanisms linked to defect dipoles such as (<InlineEquation ID="IEq1"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="339_2025_8772_Article_IEq1.gif" Format="GIF" Height="25" Rendition="HTML" Resolution="72" Type="Linedraw" Width="110" /> </InlineMediaObject> <EquationSource Format="TEX">\(\:{V}_{O}^{\cdot\:\cdot\:}-S{{n}_{S{n}^{4+}}^{2+}}^{{\prime\:}{\prime\:}}\)</EquationSource> </InlineEquation>) and (<InlineEquation ID="IEq2"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="339_2025_8772_Article_IEq2.gif" Format="GIF" Height="25" Rendition="HTML" Resolution="72" Type="Linedraw" Width="111" /> </InlineMediaObject> <EquationSource Format="TEX">\(\:{V}_{O}^{\cdot\:\cdot\:}-2C{{e}_{C{e}^{4+}}^{3+}}^{{\prime\:}}\)</EquationSource> </InlineEquation>). Electrical conduction followed an Arrhenius-type thermally activated process, dominated by doubly ionized oxygen vacancies and mixed ionic–electronic transport through electron exchange at Sn/Ce sites. The microwave dielectric response was primarily driven by electronic polarization, with optimal performance observed at x = 0.20 (ε = 12, Q×f = 23,482, <InlineEquation ID="IEq3"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="339_2025_8772_Article_IEq3.gif" Format="GIF" Height="14" Rendition="HTML" Resolution="72" Type="Linedraw" Width="22" /> </InlineMediaObject> <EquationSource Format="TEX">\(\:{\tau\:}_{f}\)</EquationSource> </InlineEquation> =108 ppm/°C). The synergy between the enhanced electrical and dielectric characteristics underscores the potential of Ce-doped Sr₂SnO₄ (SSC) ceramics for application in intermediate-temperature solid oxide fuel cell (IT-SOFC) electrodes and millimeter-wave communication systems, offering a promising avenue for advanced multifunctional ceramic materials.</p>

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Phase and structural nanoarchitectonics of Ce-Doped Sr2SnO4 for improved microwave dielectric and electrical properties

  • 期刊论文

  • 发表日期：

    2025年7月22日

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  • Upendra Kumar,
  • Satyam Kumar,
  • Abhishek Singh,
  • Piyush Kumar Sonkar

摘要

To support the advancement of layered perovskite ceramics for next-generation wireless and millimeter-wave communication technologies, a series of Sr2Sn1−xCexO4 (x = 0, 0.10, 0.20, 0.30, 0.40, and 0.50) (SSC) were synthesized via the conventional solid-state reaction method, followed by calcination at 1100 °C and sintering at 1300 °C. Structural analysis through X-ray diffraction (XRD) confirmed the formation of a single-phase tetragonal crystal structure (space group I4/mmm) for compositions up to x = 0.20. Beyond this concentration, the emergence of a secondary Sr2CeO4 phase indicated a solubility limit for Ce substitution at the Sn site between x = 0.20 and x = 0.30. This structural evolution was further corroborated by FTIR and Raman spectroscopy, which supported the phase transition and changes in local bonding environments. Microstructural examinations revealed that Ce doping significantly influenced grain morphology and agglomeration tendencies. The coexistence of oxygen vacancies, interstitials, and multivalent cations—namely Sn2+/Sn4+ and Ce2+/Ce3+/Ce4+ played a crucial role in modulating the electrical and microwave dielectric behavior. Dielectric properties were predominantly governed by orientational polarization mechanisms linked to defect dipoles such as ( \(\:{V}_{O}^{\cdot\:\cdot\:}-S{{n}_{S{n}^{4+}}^{2+}}^{{\prime\:}{\prime\:}}\) ) and ( \(\:{V}_{O}^{\cdot\:\cdot\:}-2C{{e}_{C{e}^{4+}}^{3+}}^{{\prime\:}}\) ). Electrical conduction followed an Arrhenius-type thermally activated process, dominated by doubly ionized oxygen vacancies and mixed ionic–electronic transport through electron exchange at Sn/Ce sites. The microwave dielectric response was primarily driven by electronic polarization, with optimal performance observed at x = 0.20 (ε = 12, Q×f = 23,482, \(\:{\tau\:}_{f}\) =108 ppm/°C). The synergy between the enhanced electrical and dielectric characteristics underscores the potential of Ce-doped Sr₂SnO₄ (SSC) ceramics for application in intermediate-temperature solid oxide fuel cell (IT-SOFC) electrodes and millimeter-wave communication systems, offering a promising avenue for advanced multifunctional ceramic materials.