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 (<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 GHz and 107,563 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 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 <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 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 ppm/°C. These results highlight the exceptional potential of (Sr1-xNdx)2SnO4 ceramics for deployment in next-generation millimeter-wave communication technologies.

Structural insights, bond-valence analysis, and enhanced microwave dielectric Properties of (Sr_1-xNd_x)₂SnO₄ Ruddlesden-Popper oxides

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发表日期：

2025年6月21日

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

摘要

Ceramics with the composition (Sr_1-xNd_x)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 (Sr_1-xNd_x)₂SnO₄ ceramics for deployment in next-generation millimeter-wave communication technologies.

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

摘要

Structural insights, bond-valence analysis, and enhanced microwave dielectric Properties of (Sr_1-xNd_x)₂SnO₄ Ruddlesden-Popper oxides