{"title":"NdF3-Nd2O3 和 NdF3-SrF2-Nd2O3 体系中氟化物-氧化物复合材料的合成与离子电导率","authors":"N. I. Sorokin, I. I. Buchinskaya, D. N. Karimov","doi":"10.1134/s1063774523600072","DOIUrl":null,"url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>Fluoride–oxide composites 99NdF<sub>3</sub>⋅1Nd<sub>2</sub>O<sub>3</sub>, 98NdF<sub>3</sub>⋅2Nd<sub>2</sub>O<sub>3</sub>, 97NdF<sub>3</sub>⋅3Nd<sub>2</sub>O<sub>3</sub>, 92NdF<sub>3</sub>⋅5SrF<sub>2</sub>⋅3Nd<sub>2</sub>O<sub>3</sub>, and 91NdF<sub>3</sub>⋅5SrF<sub>2</sub>⋅4Nd<sub>2</sub>O<sub>3</sub> (mol %) have been fabricated in the NdF<sub>3</sub>–Nd<sub>2</sub>O<sub>3</sub> and NdF<sub>3</sub>–SrF<sub>2</sub>–Nd<sub>2</sub>O<sub>3</sub> systems by the directional crystallization technique. It is found that the target tysonite-type Nd<span>\\(_{{1-x}}\\)</span>Sr<sub><i>x</i></sub>(O,F)<span>\\(_{{3-\\delta }}\\)</span> solid solution is partially decomposed upon cooling with segregation of nonstoichiometric modifications based on the NdO<span>\\(_{{1-x}}\\)</span>F<span>\\(_{{1 + 2x}}\\)</span> phase. The electrical conductivity of the composites has been analyzed by impedance spectroscopy in the temperature range of 294–522 K. The σ<sub>dc</sub> values at 500 K are 5.2 × 10<sup>–4</sup>, 6.5 × 10<sup>–4</sup>, and 2 × 10<sup>–3</sup> S/cm for 99NdF<sub>3</sub>⋅1Nd<sub>2</sub>O<sub>3</sub>, 97NdF<sub>3</sub>⋅3Nd<sub>2</sub>O<sub>3</sub>, and 92NdF<sub>3</sub>⋅5SrF<sub>2</sub>⋅3Nd<sub>2</sub>O<sub>3</sub>, respectively; after doping of SrF<sub>2</sub> into the composite, the conductivity increases by a factor of 4 due to heterovalent substitutions of cations Sr<sup>2+</sup> for Nd<sup>3+</sup> and formation of anion vacancies. It is shown that cationic substitutions are much more efficient (in comparison with anionic substitutions) for the mechanism of ionic conduction in tysonite-type solid solutions. The σ<sub>dc</sub> value of oxofluoride composite 92NdF<sub>3</sub>⋅5SrF<sub>2</sub>⋅3Nd<sub>2</sub>O<sub>3</sub> is larger than that for fluoride composite 70NdF<sub>3</sub>⋅30SrF<sub>2</sub> by a factor of 50 at room temperature. The composites under study can be applied as medium-temperature solid-state sensors for simultaneous detection of oxygen and fluorine.</p>","PeriodicalId":527,"journal":{"name":"Crystallography Reports","volume":null,"pages":null},"PeriodicalIF":0.6000,"publicationDate":"2024-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Synthesis and Ionic Conductivity of Fluoride–Oxide Composites in NdF3–Nd2O3 and NdF3–SrF2–Nd2O3 Systems\",\"authors\":\"N. I. Sorokin, I. I. Buchinskaya, D. N. Karimov\",\"doi\":\"10.1134/s1063774523600072\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<h3 data-test=\\\"abstract-sub-heading\\\">Abstract</h3><p>Fluoride–oxide composites 99NdF<sub>3</sub>⋅1Nd<sub>2</sub>O<sub>3</sub>, 98NdF<sub>3</sub>⋅2Nd<sub>2</sub>O<sub>3</sub>, 97NdF<sub>3</sub>⋅3Nd<sub>2</sub>O<sub>3</sub>, 92NdF<sub>3</sub>⋅5SrF<sub>2</sub>⋅3Nd<sub>2</sub>O<sub>3</sub>, and 91NdF<sub>3</sub>⋅5SrF<sub>2</sub>⋅4Nd<sub>2</sub>O<sub>3</sub> (mol %) have been fabricated in the NdF<sub>3</sub>–Nd<sub>2</sub>O<sub>3</sub> and NdF<sub>3</sub>–SrF<sub>2</sub>–Nd<sub>2</sub>O<sub>3</sub> systems by the directional crystallization technique. It is found that the target tysonite-type Nd<span>\\\\(_{{1-x}}\\\\)</span>Sr<sub><i>x</i></sub>(O,F)<span>\\\\(_{{3-\\\\delta }}\\\\)</span> solid solution is partially decomposed upon cooling with segregation of nonstoichiometric modifications based on the NdO<span>\\\\(_{{1-x}}\\\\)</span>F<span>\\\\(_{{1 + 2x}}\\\\)</span> phase. The electrical conductivity of the composites has been analyzed by impedance spectroscopy in the temperature range of 294–522 K. The σ<sub>dc</sub> values at 500 K are 5.2 × 10<sup>–4</sup>, 6.5 × 10<sup>–4</sup>, and 2 × 10<sup>–3</sup> S/cm for 99NdF<sub>3</sub>⋅1Nd<sub>2</sub>O<sub>3</sub>, 97NdF<sub>3</sub>⋅3Nd<sub>2</sub>O<sub>3</sub>, and 92NdF<sub>3</sub>⋅5SrF<sub>2</sub>⋅3Nd<sub>2</sub>O<sub>3</sub>, respectively; after doping of SrF<sub>2</sub> into the composite, the conductivity increases by a factor of 4 due to heterovalent substitutions of cations Sr<sup>2+</sup> for Nd<sup>3+</sup> and formation of anion vacancies. It is shown that cationic substitutions are much more efficient (in comparison with anionic substitutions) for the mechanism of ionic conduction in tysonite-type solid solutions. The σ<sub>dc</sub> value of oxofluoride composite 92NdF<sub>3</sub>⋅5SrF<sub>2</sub>⋅3Nd<sub>2</sub>O<sub>3</sub> is larger than that for fluoride composite 70NdF<sub>3</sub>⋅30SrF<sub>2</sub> by a factor of 50 at room temperature. The composites under study can be applied as medium-temperature solid-state sensors for simultaneous detection of oxygen and fluorine.</p>\",\"PeriodicalId\":527,\"journal\":{\"name\":\"Crystallography Reports\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":0.6000,\"publicationDate\":\"2024-02-06\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Crystallography Reports\",\"FirstCategoryId\":\"88\",\"ListUrlMain\":\"https://doi.org/10.1134/s1063774523600072\",\"RegionNum\":4,\"RegionCategory\":\"材料科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q4\",\"JCRName\":\"CRYSTALLOGRAPHY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Crystallography Reports","FirstCategoryId":"88","ListUrlMain":"https://doi.org/10.1134/s1063774523600072","RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"CRYSTALLOGRAPHY","Score":null,"Total":0}
Synthesis and Ionic Conductivity of Fluoride–Oxide Composites in NdF3–Nd2O3 and NdF3–SrF2–Nd2O3 Systems
Abstract
Fluoride–oxide composites 99NdF3⋅1Nd2O3, 98NdF3⋅2Nd2O3, 97NdF3⋅3Nd2O3, 92NdF3⋅5SrF2⋅3Nd2O3, and 91NdF3⋅5SrF2⋅4Nd2O3 (mol %) have been fabricated in the NdF3–Nd2O3 and NdF3–SrF2–Nd2O3 systems by the directional crystallization technique. It is found that the target tysonite-type Nd\(_{{1-x}}\)Srx(O,F)\(_{{3-\delta }}\) solid solution is partially decomposed upon cooling with segregation of nonstoichiometric modifications based on the NdO\(_{{1-x}}\)F\(_{{1 + 2x}}\) phase. The electrical conductivity of the composites has been analyzed by impedance spectroscopy in the temperature range of 294–522 K. The σdc values at 500 K are 5.2 × 10–4, 6.5 × 10–4, and 2 × 10–3 S/cm for 99NdF3⋅1Nd2O3, 97NdF3⋅3Nd2O3, and 92NdF3⋅5SrF2⋅3Nd2O3, respectively; after doping of SrF2 into the composite, the conductivity increases by a factor of 4 due to heterovalent substitutions of cations Sr2+ for Nd3+ and formation of anion vacancies. It is shown that cationic substitutions are much more efficient (in comparison with anionic substitutions) for the mechanism of ionic conduction in tysonite-type solid solutions. The σdc value of oxofluoride composite 92NdF3⋅5SrF2⋅3Nd2O3 is larger than that for fluoride composite 70NdF3⋅30SrF2 by a factor of 50 at room temperature. The composites under study can be applied as medium-temperature solid-state sensors for simultaneous detection of oxygen and fluorine.
期刊介绍:
Crystallography Reports is a journal that publishes original articles short communications, and reviews on various aspects of crystallography: diffraction and scattering of X-rays, electrons, and neutrons, determination of crystal structure of inorganic and organic substances, including proteins and other biological substances; UV-VIS and IR spectroscopy; growth, imperfect structure and physical properties of crystals; thin films, liquid crystals, nanomaterials, partially disordered systems, and the methods of studies.