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Abstract <p>The possibility is studied to obtain middle-entropy perovskite PbSc<sub>1/4</sub>In<sub>1/4</sub>Nb<sub>1/4</sub>Ta<sub>1/4</sub>O<sub>3</sub> by the sol-gel method from citric acid solutions containing F<sup>–</sup> ions. According to synchrotron X-ray diffraction data, the synthesis passes through a low-temperature stage of forming a phase with the pyrochlore structure (500-600&#xa0;°C). As the temperature increases (800&#xa0;°C), this phase transforms into a phase with the perovskite structure. The composition of the synthesis product appreciably deviates from the set one and corresponds to formula Pb<sub>1–0.9</sub>Sc<sub>0.431±0.016</sub>In<sub>0.142±0.014</sub>Nb<sub>0.228±0.013</sub>Ta<sub>0.199±0.005</sub>O<sub>3–δ</sub>F<sub>δ</sub>. Indium, niobium, and tantalum concentrations are underestimated in it with regard to the volatility of their fluorides removed from the system at early stages of the xerogel formation during evaporation of the solution. The fluorine concentation decreases in the samples with increasing temperature due to high-temperature vapor phase hydrolysis. There is the optimal fluorine concentration (~0.04&#xa0;at.&#xa0;% per PSINT mol) reached at 800&#xa0;°C and stabilizing the perovskite structure. When the F<sup>–</sup> concentration decreases up to zero after annealing at 1100&#xa0;°C, perovskite almost completely transforms into pyrochlore.</p>

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Sol-Gel Synthesis of Middle Entropy Perovskite PbSc1/4In1/4Nb1/4Ta1/4O3 in the Presence of Fluoride Ions

  • 期刊论文

  • 发表日期：

    2025年11月1日

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  • I. V. Lisnevskaya,
  • E. A. Reshetnikova,
  • I. G. Sheptun,
  • O. Yu. Grapenko,
  • A. V. Dobrydin,
  • E. S. Kulikova,
  • V. G. Vlasenko,
  • N. V. Ter-Oganesyan

摘要

Abstract

The possibility is studied to obtain middle-entropy perovskite PbSc1/4In1/4Nb1/4Ta1/4O3 by the sol-gel method from citric acid solutions containing F– ions. According to synchrotron X-ray diffraction data, the synthesis passes through a low-temperature stage of forming a phase with the pyrochlore structure (500-600 °C). As the temperature increases (800 °C), this phase transforms into a phase with the perovskite structure. The composition of the synthesis product appreciably deviates from the set one and corresponds to formula Pb1–0.9Sc0.431±0.016In0.142±0.014Nb0.228±0.013Ta0.199±0.005O3–δFδ. Indium, niobium, and tantalum concentrations are underestimated in it with regard to the volatility of their fluorides removed from the system at early stages of the xerogel formation during evaporation of the solution. The fluorine concentation decreases in the samples with increasing temperature due to high-temperature vapor phase hydrolysis. There is the optimal fluorine concentration (~0.04 at. % per PSINT mol) reached at 800 °C and stabilizing the perovskite structure. When the F– concentration decreases up to zero after annealing at 1100 °C, perovskite almost completely transforms into pyrochlore.