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<p>This study develops a composition-resolved Y<sub>2</sub>O<sub>3</sub>-modified α-Fe<sub>2</sub>O<sub>3</sub> nanocomposite platform for tuning interfacial polarization, surface oxygen chemistry, and frequency-dependent charge transport in oxide dielectrics. Nanocomposites containing 1, 3, 5, and 10&#xa0;mol% Y<sub>2</sub>O<sub>3</sub> were synthesized through a sol-gel-assisted chemical precipitation route and characterized by XRD, FT-IR, Raman, XPS, FE-SEM/EDX, and broadband dielectric spectroscopy over the 1&#xa0;kHz-10&#xa0;MHz range. XRD analysis confirmed the preservation of the dominant hematite α-Fe<sub>2</sub>O<sub>3</sub> framework and quantified the composition-dependent structural response: the lattice parameters changed from a = 5.0116 ± 0.0056 Å and c = 13.6334 ± 0.0421 Å for pristine Fe<sub>2</sub>O<sub>3</sub> to a = 5.0211 ± 0.0036 Å and c = 13.6767 ± 0.0275 Å for Fe<sub>2</sub>O<sub>3</sub>-10Y<sub>2</sub>O<sub>3</sub>, while the median Scherrer crystallite size increased from 28.09 to 37.43&#xa0;nm across the same comparison. FT-IR, Raman, and XPS results collectively revealed systematic modification of Fe-O/Y-O bonding environments, surface hydroxylation, and chemically distinct oxygen-related interfacial sites, while FE-SEM/EDX verified progressive Y distribution with the Y content increasing from 2.4 ± 0.1 wt% to 10.9 ± 0.1 wt% in the modified series. At 1&#xa0;kHz, the dielectric constant increased from 10.133 ± 0.015 for pristine Fe<sub>2</sub>O<sub>3</sub> to 14.743 ± 0.005 for Fe<sub>2</sub>O<sub>3</sub>-10Y<sub>2</sub>O<sub>3</sub>, corresponding to a 45.5% enhancement; dielectric loss increased from 0.650 ± 0.006 to 0.959 ± 0.010, whereas tan δ remained narrowly distributed between 0.064 and 0.065. The AC conductivity increased from (3.618 ± 0.034) × 10<sup>⁻8</sup> to (5.336 ± 0.057) × 10<sup>⁻8</sup> S/cm, supporting composition-tunable localized transport while retaining a low-conductivity dielectric regime. The combined structural, chemical, morphological, and dielectric evidence demonstrates that Y<sub>2</sub>O<sub>3</sub> modification reinforces α-Fe<sub>2</sub>O<sub>3</sub> through interface-assisted polarization and controlled relaxation dynamics, making these nanocomposites suitable for moderate-permittivity dielectric layers, capacitive oxide components, and frequency-dependent electronic applications.</p>

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Tailoring interfacial polarization and surface oxygen chemistry in Y2O3-modified α-Fe2O3 nanocomposites for enhanced dielectric response and charge transport behavior

  • 期刊论文

  • 发表日期：

    2026年7月30日

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  • Cevher Kursat Macit,
  • Ezgi Gurgenc,
  • Melek Güner,
  • Halil İbrahim Yamaç,
  • Merve Ayık,
  • Betül Çiçek Özkan,
  • Bünyamin Aksakal,
  • Turan Gurgenc

摘要

This study develops a composition-resolved Y2O3-modified α-Fe2O3 nanocomposite platform for tuning interfacial polarization, surface oxygen chemistry, and frequency-dependent charge transport in oxide dielectrics. Nanocomposites containing 1, 3, 5, and 10 mol% Y2O3 were synthesized through a sol-gel-assisted chemical precipitation route and characterized by XRD, FT-IR, Raman, XPS, FE-SEM/EDX, and broadband dielectric spectroscopy over the 1 kHz-10 MHz range. XRD analysis confirmed the preservation of the dominant hematite α-Fe2O3 framework and quantified the composition-dependent structural response: the lattice parameters changed from a = 5.0116 ± 0.0056 Å and c = 13.6334 ± 0.0421 Å for pristine Fe2O3 to a = 5.0211 ± 0.0036 Å and c = 13.6767 ± 0.0275 Å for Fe2O3-10Y2O3, while the median Scherrer crystallite size increased from 28.09 to 37.43 nm across the same comparison. FT-IR, Raman, and XPS results collectively revealed systematic modification of Fe-O/Y-O bonding environments, surface hydroxylation, and chemically distinct oxygen-related interfacial sites, while FE-SEM/EDX verified progressive Y distribution with the Y content increasing from 2.4 ± 0.1 wt% to 10.9 ± 0.1 wt% in the modified series. At 1 kHz, the dielectric constant increased from 10.133 ± 0.015 for pristine Fe2O3 to 14.743 ± 0.005 for Fe2O3-10Y2O3, corresponding to a 45.5% enhancement; dielectric loss increased from 0.650 ± 0.006 to 0.959 ± 0.010, whereas tan δ remained narrowly distributed between 0.064 and 0.065. The AC conductivity increased from (3.618 ± 0.034) × 10⁻8 to (5.336 ± 0.057) × 10⁻8 S/cm, supporting composition-tunable localized transport while retaining a low-conductivity dielectric regime. The combined structural, chemical, morphological, and dielectric evidence demonstrates that Y2O3 modification reinforces α-Fe2O3 through interface-assisted polarization and controlled relaxation dynamics, making these nanocomposites suitable for moderate-permittivity dielectric layers, capacitive oxide components, and frequency-dependent electronic applications.