<p>Ceramics with the composition (Sr<sub>1-x</sub>Nd<sub>x</sub>)<sub>2</sub>SnO<sub>4</sub> (SNS), with 0 ≤ x ≤ 0.05, were successfully synthesized via the conventional solid-state reaction method and sintered at 1300&#xa0;°C. Rietveld refinement of X-ray diffraction data confirmed that all samples crystallized in a tetragonal structure (space group <i>I4/mmm</i>). The incorporation of Nd<sup>3+</sup> ions into the lattice was substantiated by FTIR and Raman spectroscopy, with characteristic vibrational bands at 576&#xa0;cm<sup>−1</sup> and 701&#xa0;cm<sup>−1</sup> (FTIR), and 255&#xa0;cm<sup>−1</sup> and 580&#xa0;cm<sup>−1</sup> (Raman). XPS analysis revealed Sn<sup>2+</sup> and Sn<sup>4+</sup> states alongside oxygen vacancies and interstitial defects, indicating complex charge compensation mechanisms. Microwave dielectric properties measured in the K-band exhibited a pronounced dependence on Nd doping. Substitution of Nd<sup>3+</sup> at Sr<sup>2+</sup> sites increased lattice volume, alterations in bond lengths, and distortions in bond angles, significantly influencing dielectric performance. The dielectric constant (<InlineEquation ID="IEq1"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10854_2025_15178_Article_IEq1.gif" Format="GIF" Height="12" Rendition="HTML" Resolution="72" Type="Linedraw" Width="16" /> </InlineMediaObject> <EquationSource Format="TEX">\({\varepsilon }_{r}\)</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>ε</mi> <mi>r</mi> </msub> </math></EquationSource> </InlineEquation>) ranged from 23 to 43, the quality factor (Q × f) varied between 15,838&#xa0;GHz and 107,563&#xa0;GHz, and the temperature coefficient of resonant frequency (<InlineEquation ID="IEq2"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10854_2025_15178_Article_IEq2.gif" Format="GIF" Height="14" Rendition="HTML" Resolution="72" Type="Linedraw" Width="17" /> </InlineMediaObject> <EquationSource Format="TEX">\({\tau }_{f}\)</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>τ</mi> <mi>f</mi> </msub> </math></EquationSource> </InlineEquation>) decreased from 55&#xa0;ppm/°C to 5&#xa0;ppm/°C, with all trends aligning well with theoretical and experimental ionic polarizability models. Notably, at x = 0.02, the ceramics exhibited optimal dielectric properties, with <InlineEquation ID="IEq3"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10854_2025_15178_Article_IEq1.gif" Format="GIF" Height="12" Rendition="HTML" Resolution="72" Type="Linedraw" Width="16" /> </InlineMediaObject> <EquationSource Format="TEX">\({\varepsilon }_{r}\)</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>ε</mi> <mi>r</mi> </msub> </math></EquationSource> </InlineEquation>=42, Q × f = 80,592&#xa0;GHz, and <InlineEquation ID="IEq4"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10854_2025_15178_Article_IEq2.gif" Format="GIF" Height="14" Rendition="HTML" Resolution="72" Type="Linedraw" Width="17" /> </InlineMediaObject> <EquationSource Format="TEX">\({\tau }_{f}\)</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>τ</mi> <mi>f</mi> </msub> </math></EquationSource> </InlineEquation> =30.53&#xa0;ppm/°C. These results highlight the exceptional potential of (Sr<sub>1-x</sub>Nd<sub>x</sub>)<sub>2</sub>SnO<sub>4</sub> ceramics for deployment in next-generation millimeter-wave communication technologies.</p>

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Structural insights, bond-valence analysis, and enhanced microwave dielectric Properties of (Sr1-xNdx)2SnO4 Ruddlesden-Popper oxides

  • Sushil Kumar,
  • Raj Kumar,
  • Vedika Yadav,
  • Satyam Kumar,
  • Marcos Flores Carrasco,
  • Abhishek Singh,
  • Upendra Kumar

摘要

Ceramics with the composition (Sr1-xNdx)2SnO4 (SNS), with 0 ≤ x ≤ 0.05, were successfully synthesized via the conventional solid-state reaction method and sintered at 1300 °C. Rietveld refinement of X-ray diffraction data confirmed that all samples crystallized in a tetragonal structure (space group I4/mmm). The incorporation of Nd3+ ions into the lattice was substantiated by FTIR and Raman spectroscopy, with characteristic vibrational bands at 576 cm−1 and 701 cm−1 (FTIR), and 255 cm−1 and 580 cm−1 (Raman). XPS analysis revealed Sn2+ and Sn4+ states alongside oxygen vacancies and interstitial defects, indicating complex charge compensation mechanisms. Microwave dielectric properties measured in the K-band exhibited a pronounced dependence on Nd doping. Substitution of Nd3+ at Sr2+ sites increased lattice volume, alterations in bond lengths, and distortions in bond angles, significantly influencing dielectric performance. The dielectric constant ( \({\varepsilon }_{r}\) ε r ) ranged from 23 to 43, the quality factor (Q × f) varied between 15,838 GHz and 107,563 GHz, and the temperature coefficient of resonant frequency ( \({\tau }_{f}\) τ f ) decreased from 55 ppm/°C to 5 ppm/°C, with all trends aligning well with theoretical and experimental ionic polarizability models. Notably, at x = 0.02, the ceramics exhibited optimal dielectric properties, with \({\varepsilon }_{r}\) ε r =42, Q × f = 80,592 GHz, and \({\tau }_{f}\) τ f =30.53 ppm/°C. These results highlight the exceptional potential of (Sr1-xNdx)2SnO4 ceramics for deployment in next-generation millimeter-wave communication technologies.