zldmЗаводская лаборатория. Диагностика материаловIndustrial laboratory. Diagnostics of materials1028-68612588-0187ООО «Издательство «ТЕСТ-ЗЛ»10.26896/1028-6861-2026-92-2-30-41zldm-2728Research ArticleИССЛЕДОВАНИЕ СТРУКТУРЫ И СВОЙСТВSTRUCTURE AND PROPERTIES INVESTIGATIONИсследование свойств оксидного пирохлора на основе ниобата висмута, допированного катионами Co, Mn, CrResearch of the properties of oxide pyrochlore based on bismuth niobate doped with Co, Mn, Cr cationsПетраковА. П.PetrakovA. P.

Анатолий Павлович Петраков

167001, г. Сыктывкар, Октябрьский просп., д. 55

Anatoly P. Petrakov

55, Oktyabrsky prosp., Syktyvkar, 167001

petrakov@syktsu.ruБаданинаК. А.BadaninaK. A.

Ксения Алексеевна Баданина

167001, г. Сыктывкар, Октябрьский просп., д. 55

Kseniya A. Badanina

55, Oktyabrsky prosp., Syktyvkar, 167001

СекушинН. А.SekushinN. A.

Николай Александрович Секушин

167982, г. Сыктывкар, ул. Первомайская, д. 54

Nikolay A. Sekushin

54, ul. Pervomaiskaya, Syktyvkar, 167982

КржижановскаяМ. Г.KrzhizhanovskayaM. G.

Мария Георгиевна Кржижановская

198504, г. С.-Петербург, Университетский просп., д. 26

Maria G. Krzhizhanovskaya

26, Universitetsky prosp., St. Petersburg, 198504

СелютинА. А.SelyutinA. A.

Артем Александрович Селютин

198504, г. С.-Петербург, Университетский просп., д. 26

Artyom A. Selyutin

26, Universitetsky prosp., St. Petersburg, 198504

КоролеваА. В.KorolevaA. V.

Александра Владимировна Королева

198504, г. С.-Петербург, Университетский просп., д. 26

Alexandra V. Koroleva

26, Universitetsky prosp., St. Petersburg, 198504

НекипеловС. В.NekipelovS. V.

Сергей Вячеславович Некипелов

167982, г. Сыктывкар, ул. Оплеснина, д. 4

Sergey V. Nekipelov

4, ul. Oplesnina, Syktyvkar, 167982

ЖукН. А.ZhukN. A.

Надежда Алексеевна Жук

167001, г. Сыктывкар, Октябрьский просп., д. 55

Nadezhda A. Zhuk

55, Oktyabrsky prosp., Syktyvkar, 167001

Сыктывкарский государственный университет имени Питирима СорокинаРоссияPitirim Sorokin Syktyvkar State UniversityRussian FederationИнститут химии Коми НЦ УрО РАНРоссияInstitute of Chemistry, Komi Science Center, UB RASRussian FederationСанкт-Петербургский государственный университетРоссияSt. Petersburg State UniversityRussian FederationИнститут физики и математики Коми НЦ УрО РАНРоссияInstitute of Physics and Mathematics, Komi Science Center, UB RASRussian Federation2026230220269223041Copyright © Петраков А.П., Баданина К.А., Секушин Н.А., Кржижановская М.Г., Селютин А.А., Королева А.В., Некипелов С.В., Жук Н.А., 20262026Петраков А.П., Баданина К.А., Секушин Н.А., Кржижановская М.Г., Селютин А.А., Королева А.В., Некипелов С.В., Жук Н.А.Petrakov A.P., Badanina K.A., Sekushin N.A., Krzhizhanovskaya M.G., Selyutin A.A., Koroleva A.V., Nekipelov S.V., Zhuk N.A.Данная работа распространяется под лицензией Creative Commons Attribution 4.0.This work is licensed under a Creative Commons Attribution 4.0 License.https://www.zldm.ru/jour/article/view/2728

Синтетические оксидные пирохлоры характеризуются широким спектром уникальных свойств. Особый интерес с точки зрения взаимного влияния допантов друг на друга и на функциональные свойства соединения представляют мультиэлементные пирохлоры, допированные несколькими переходными элементами. В работе представлены результаты исследования электрических и оптических свойств оксидного пирохлора на основе ниобата висмута, допированного катионами кобальта, хрома и марганца в эквимолярных количествах. Методом XPS исследовали зарядовое состояние катионов в составе оксидного пирохлора Bi1,73Mn1/3Cr1/3Co1/3Nb2O9 + δ, синтезированного методом твердофазной реакции. Параметры XPS-спектров для мультиэлементного пирохлора сравнивали с параметрами оксидов переходных элементов. Показано, что для пирохлора наблюдается характерный сдвиг Bi4f- и Nb3d-спектров в область меньших энергий на 0,20 и 0,65 эВ соответственно. Катионы кобальта и марганца находятся в смешанном зарядовом состоянии, преимущественно имеют эффективный заряд +2 и +3. Cr2p-спектр представляет суперпозицию спектров от ионов хрома в зарядовом состоянии +3, +4 и +6. Установлено также, что микроструктура керамики малопористая, образована сплавленными между собой зернами размером 2 мкм. Ширина запрещенной зоны для прямого разрешенного перехода составляет 1,85 эВ. При 24 °C диэлектрическая проницаемость беспримесного образца и образца с примесями в диапазоне 104 – 106 Гц слабо зависит от частоты и составляет 70 и 80, тангенс диэлектрических потерь для обоих образцов при 1 МГц — 0,002, энергия активации высокотемпературной проводимости — 0,78 и 0,71 эВ соответственно. Полученные результаты могут быть использованы при совершенствовании методики применения материала в качестве, например, фотокатализатора в видимой области излучения.

Synthetic oxide pyrochlores are characterized by a wide range of unique properties. Multi-element pyrochlores doped with several transition elements are of particular interest in terms of the mutual influence of dopants on each other and on the functional properties of the compound. This paper presents the results of a study of the electrical and optical properties of oxide pyrochlore based on bismuth niobate doped with cobalt, chromium, and manganese cations in equimolar amounts. XPS was used to study the charge state of cations in the oxide pyrochlore Bi1.73Mn1/3Cr1/3Co1/3Nb2O9 + δ, synthesized by a solid-phase reaction. The XPS spectral parameters for the multi-element pyrochlore were compared with those of transition element oxides. It was shown that pyrochlore exhibits a characteristic shift of the Bi4f and Nb3d spectra toward lower energies by 0.20 and 0.65 eV, respectively. The cobalt and manganese cations are in a mixed charge state, predominantly with an effective charge of +2 and +3. The Cr2p spectrum is a superposition of the spectra of chromium ions in charge states of +3, +4, and +6. It was also established that the ceramic microstructure is low in porosity, formed by fused grains measuring 2 μm. The band gap for the direct allowed transition is 1.85 eV. At 24 °C, the permittivity of the pure and doped samples in the range of 104 – 106 Hz depends weakly on frequency and is 70 and 80, respectively. The dielectric loss tangent for both samples at 1 MHz is 0.002, and the activation energy for high-temperature conductivity is 0.78 and 0.71 eV, respectively. The obtained results can be used to improve the methodology for using the material as, for example, a photocatalyst in the visible spectrum.

электрические свойствапирохлоримпеданс-спектроскопия3d-элементыРФЭСширина запрещенной зоныelectrical propertiespyrochloreimpedance spectroscopy3d elementsXPSband gapReferencesHiroi Z., Yamaura J.-I., Yonezawa S., et al. Chemical trends of superconducting properties in pyrochlore oxides / Phys. C: Superconduct. Its Appl. 2007. Vols. 460 – 462. P. 20 – 27. DOI: 10.1016/j.physc.2007.03.023Hiroi Z., Yamaura J.-I., Yonezawa S., et al. Chemical trends of superconducting properties in pyrochlore oxides / Phys. C: Superconduct. Its Appl. 2007. Vols. 460 – 462. P. 20 – 27. DOI: 10.1016/j.physc.2007.03.023Giampaoli G., Siritanon T., Day B., et al. Temperature independent low loss dielectrics based on quaternary pyrochlore oxides / Progr. Solid State Chem. 2018. Vol. 50. P. 16 – 23. DOI: 10.1016/j.progsolidstchem.2018.06.001Giampaoli G., Siritanon T., Day B., et al. Temperature independent low loss dielectrics based on quaternary pyrochlore oxides / Progr. Solid State Chem. 2018. Vol. 50. P. 16 – 23. DOI: 10.1016/j.progsolidstchem.2018.06.001Pandey J., Shrivastava V., Nagarajan R. Metastable Bi2Zr2O7 with pyrochlore-like structure: stabilization, oxygen ion conductivity, and catalytic properties / Inorg. Chem. 2018. Vol. 57. P. 13667 – 13678. DOI: 10.1021/acs.inorgchem.8b02258Pandey J., Shrivastava V., Nagarajan R. Metastable Bi2Zr2O7 with pyrochlore-like structure: stabilization, oxygen ion conductivity, and catalytic properties / Inorg. Chem. 2018. Vol. 57. P. 13667 – 13678. DOI: 10.1021/acs.inorgchem.8b02258Murugesan S., Huda M., Yan Y., et al. Band-engineered bismuth titanate pyrochlores for visible light photocatalysis / J. Phys. Chem. 2010. Vol. 114. P. 10598 – 10605. DOI: 10.1021/jp906252rMurugesan S., Huda M., Yan Y., et al. Band-engineered bismuth titanate pyrochlores for visible light photocatalysis / J. Phys. Chem. 2010. Vol. 114. P. 10598 – 10605. DOI: 10.1021/jp906252rCann D. P., Randall C. A., Shrout T. R. Investigation of the dielectric properties of bismuth pyrochlores / Solid State Comm. 1996. Vol. 100. P. 529 – 534. DOI: 10.1016/0038-1098(96)00012-9Cann D. P., Randall C. A., Shrout T. R. Investigation of the dielectric properties of bismuth pyrochlores / Solid State Comm. 1996. Vol. 100. P. 529 – 534. DOI: 10.1016/0038-1098(96)00012-9Yu S., Li L., Zheng H. BMN-based transparent capacitors with high dielectric tunability / J. Alloys Compounds. 2017. Vol. 699. P. 68 – 72. DOI: 10.1016/j.jallcom.2016.12.333Yu S., Li L., Zheng H. BMN-based transparent capacitors with high dielectric tunability / J. Alloys Compounds. 2017. Vol. 699. P. 68 – 72. DOI: 10.1016/j.jallcom.2016.12.333Guo Q., Li L., Yu S., et al. Temperature-stable dielectrics based on Cu-doped Bi2Mg2/3Nb4/3O7 pyrochlore ceramics for LTCC / Ceramics Int. 2018. Vol. 44. P. 333 – 338. DOI: 10.1016/j.ceramint.2017.09.177Guo Q., Li L., Yu S., et al. Temperature-stable dielectrics based on Cu-doped Bi2Mg2/3Nb4/3O7 pyrochlore ceramics for LTCC / Ceramics Int. 2018. Vol. 44. P. 333 – 338. DOI: 10.1016/j.ceramint.2017.09.177Huiling D., Xi Y. Synthesis and dielectric properties development of new thermal stable bismuth pyrochlores / J. Phys. Chem. Solids. 2002. Vol. 63. P. 2123 – 2128. DOI: 10.1016/s0022-3697(02)00262-7Huiling D., Xi Y. Synthesis and dielectric properties development of new thermal stable bismuth pyrochlores / J. Phys. Chem. Solids. 2002. Vol. 63. P. 2123 – 2128. DOI: 10.1016/s0022-3697(02)00262-7Du H., Wang H., Yao X. Observations on structural evolution and dielectric properties of oxygen-deficient pyrochlores / Ceramics Int. 2004. Vol. 30. P. 1383 – 1387. DOI: 10.1016/j.ceramint.2003.12.091Du H., Wang H., Yao X. Observations on structural evolution and dielectric properties of oxygen-deficient pyrochlores / Ceramics Int. 2004. Vol. 30. P. 1383 – 1387. DOI: 10.1016/j.ceramint.2003.12.091Vanderah T. A., Lufaso M. W., Adler A. U., et al. Subsolidus phase equilibria and properties in the system Bi2O3:Mn2O3 ± x:Nb2O5 / J. Solid State Chem. 2006. Vol. 179. P. 3467 – 3477. DOI: 10.1016/j.jssc.2006.07.014Vanderah T. A., Lufaso M. W., Adler A. U., et al. Subsolidus phase equilibria and properties in the system Bi2O3:Mn2O3 ± x:Nb2O5 / J. Solid State Chem. 2006. Vol. 179. P. 3467 – 3477. DOI: 10.1016/j.jssc.2006.07.014Vanderah T., Siegrist T., Lufaso M., et al. Phase formation and properties in the system Bi2O3:2CoO1 + x:Nb2O5 / Eur. J. Inorg. Chem. 2006. Vol. 23. P. 4908 – 4914. DOI: 10.1002/ejic.200600661Vanderah T., Siegrist T., Lufaso M., et al. Phase formation and properties in the system Bi2O3:2CoO1 + x:Nb2O5 / Eur. J. Inorg. Chem. 2006. Vol. 23. P. 4908 – 4914. DOI: 10.1002/ejic.200600661Miles G. C., West A. R. Pyrochlore phases in the system ZnO-Bi2O3-Sb2O5: I. Stoichiometries and Phase Equilibria / J. Am. Ceram. Soc. 2006. Vol. 89. P. 1042 – 1046. DOI: 10.1111/j.1551-2916.2005.00799.xMiles G. C., West A. R. Pyrochlore phases in the system ZnO-Bi2O3-Sb2O5: I. Stoichiometries and Phase Equilibria / J. Am. Ceram. Soc. 2006. Vol. 89. P. 1042 – 1046. DOI: 10.1111/j.1551-2916.2005.00799.xValant M., Suvorov D. The Bi2O3-Nb2O5-NiO phase diagram / J. Am. Ceram. Soc. 2005. Vol. 88. P. 2540 – 2543. DOI: 10.1111/j.1551-2916.2005.00439.xValant M., Suvorov D. The Bi2O3-Nb2O5-NiO phase diagram / J. Am. Ceram. Soc. 2005. Vol. 88. P. 2540 – 2543. DOI: 10.1111/j.1551-2916.2005.00439.xSubramanian M., Aravamudan G., Subba Rao G. Oxide pyrochlores: a review / Progr. Solid State Chem. 1983. Vol. 15. P. 55 – 143. DOI: 10.1016/00796786(83)90001-8Subramanian M., Aravamudan G., Subba Rao G. Oxide pyrochlores: a review / Progr. Solid State Chem. 1983. Vol. 15. P. 55 – 143. DOI: 10.1016/00796786(83)90001-8Hassan A., Mustafa G., Abbas S., et al. Correlation of La-mediated structural transition and dielectric relaxation in Bi2Mg2/3Nb4/3O7 pyrochlores / Ceramics Int. 2019. Vol. 45. P. 14576 – 14585. DOI: 10.1016/j.ceramint.2019.04.175Hassan A., Mustafa G., Abbas S., et al. Correlation of La-mediated structural transition and dielectric relaxation in Bi2Mg2/3Nb4/3O7 pyrochlores / Ceramics Int. 2019. Vol. 45. P. 14576 – 14585. DOI: 10.1016/j.ceramint.2019.04.175Zhuk N. A., Sekushin N. A., Krzhizhanovskaya M. G., et al. Multiple relaxation, reversible electrical breakdown and bipolar conductivity of pyrochlore-type Bi2Cu0.5Zn0.5Ta2O9 ceramics / Solid State Ionics. 2022. Vol. 377. Art. 115868. DOI: 10.1016/j.ssi.2022.115868Zhuk N. A., Sekushin N. A., Krzhizhanovskaya M. G., et al. Multiple relaxation, reversible electrical breakdown and bipolar conductivity of pyrochlore-type Bi2Cu0.5Zn0.5Ta2O9 ceramics / Solid State Ionics. 2022. Vol. 377. Art. 115868. DOI: 10.1016/j.ssi.2022.115868Valant M. Dielectric relaxations in Bi2O3-Nb2O5-NiO cubic pyrochlores / J. Am. Ceram. Soc. 2009. Vol. 92. P. 955 – 958. DOI: 10.1111/j.15512916.2009.02984.xValant M. Dielectric relaxations in Bi2O3-Nb2O5-NiO cubic pyrochlores / J. Am. Ceram. Soc. 2009. Vol. 92. P. 955 – 958. DOI: 10.1111/j.15512916.2009.02984.xZhuk N. A., Krzhizhanovskaya M. G., Koroleva A. V., et al. Spectroscopic characterization of cobalt doped bismuth tantalate pyrochlore / Solid State Sci. 2022. Vol. 125. Art. 106820. DOI: 10.1016/j.solidstatesciences.2022.106820Zhuk N. A., Krzhizhanovskaya M. G., Koroleva A. V., et al. Spectroscopic characterization of cobalt doped bismuth tantalate pyrochlore / Solid State Sci. 2022. Vol. 125. Art. 106820. DOI: 10.1016/j.solidstatesciences.2022.106820Zhuk N. A., Krzhizhanovskaya M. G., Sekushin N. A., et al. Crystal structure, dielectric and thermal properties of cobalt doped bismuth tantalate pyrochlore / J. Mater. Res. Technol. 2023. Vol. 22. P. 1791 – 1799. DOI: 10.1016/j.jmrt.2022.12.059Zhuk N. A., Krzhizhanovskaya M. G., Sekushin N. A., et al. Crystal structure, dielectric and thermal properties of cobalt doped bismuth tantalate pyrochlore / J. Mater. Res. Technol. 2023. Vol. 22. P. 1791 – 1799. DOI: 10.1016/j.jmrt.2022.12.059Hassan A., Mustafa G., Abbas S., et al. Correlation of La-mediated structural transition and dielectric relaxation in Bi2Mg2/3Nb4/3O7 pyrochlores / Ceramics Int. 2019. Vol. 45. P. 14576 – 14585. DOI: 10.1016/j.ceramint.2019.04.175Hassan A., Mustafa G., Abbas S., et al. Correlation of La-mediated structural transition and dielectric relaxation in Bi2Mg2/3Nb4/3O7 pyrochlores / Ceramics Int. 2019. Vol. 45. P. 14576 – 14585. DOI: 10.1016/j.ceramint.2019.04.175Tan P. Y., Tan K. B., Khaw C. C., et al. Phase equilibria and dielectric properties of Bi3 + (5/2)xMg2 – xNb3 – (3/2)xO14 – x cubic pyrochlores / Ceramics Int. 2014. Vol. 40. P. 4237 – 4246. DOI: 10.1016/j.ceramint.2013.08.087Tan P. Y., Tan K. B., Khaw C. C., et al. Phase equilibria and dielectric properties of Bi3 + (5/2)xMg2 – xNb3 – (3/2)xO14 – x cubic pyrochlores / Ceramics Int. 2014. Vol. 40. P. 4237 – 4246. DOI: 10.1016/j.ceramint.2013.08.087Dasin N. A. M., Tan K. B., Khaw C. C., et al. Doping mechanisms and dielectric properties of Ca-doped bismuth magnesium niobate pyrochlores / Mater. Chem. Phys. 2019. Vol. 242. Art. 122558. DOI: 10.1016/j.matchemphys.2019.122558Dasin N. A. M., Tan K. B., Khaw C. C., et al. Doping mechanisms and dielectric properties of Ca-doped bismuth magnesium niobate pyrochlores / Mater. Chem. Phys. 2019. Vol. 242. Art. 122558. DOI: 10.1016/j.matchemphys.2019.122558Piir I. V., Prikhodko D. A., Ignatchenko S. V., et al. Preparation and structural investigations of the mixed bismuth niobates, containing transition metals / Solid State Ionics. 1997. Vol. 101 – 103. P. 1141 – 1146. DOI: 10.1016/s0167-2738(97)00374-3Piir I. V., Prikhodko D. A., Ignatchenko S. V., et al. Preparation and structural investigations of the mixed bismuth niobates, containing transition metals / Solid State Ionics. 1997. Vol. 101 – 103. P. 1141 – 1146. DOI: 10.1016/s0167-2738(97)00374-3Ismunandar, Kamiyama T., Oikawa K., et al. Static bismuth disorder in Bi2 – x(CrTa)O7 – y / Mater. Res. Bull. 2004. Vol. 39. P. 553 – 560. DOI: 10.1016/j.materresbull.2003.12.017Ismunandar, Kamiyama T., Oikawa K., et al. Static bismuth disorder in Bi2 – x(CrTa)O7 – y / Mater. Res. Bull. 2004. Vol. 39. P. 553 – 560. DOI: 10.1016/j.materresbull.2003.12.017Zhuk N. A., Sekushin N. A., Krzhizhanovskaya M. G., et al. Cr-doped bismuth tantalate pyrochlore: electrical and thermal properties, crystal structure and ESR, NEXAFS, XPS spectroscopy / Mater. Res. Bull. 2023. Vol. 158. Art. 112067. DOI: 10.1016/j.materresbull.2022.112067Zhuk N. A., Sekushin N. A., Krzhizhanovskaya M. G., et al. Cr-doped bismuth tantalate pyrochlore: electrical and thermal properties, crystal structure and ESR, NEXAFS, XPS spectroscopy / Mater. Res. Bull. 2023. Vol. 158. Art. 112067. DOI: 10.1016/j.materresbull.2022.112067Zhuk N. A., Krzhizhanovskaya M. G., Belyy V. A., et al. High temperature crystal chemistry of α-, β-, and γ-BiNbO4 polymorphs / Inorg. Chem. 2019. Vol. 58. P. 1518 – 1525. DOI: 10.1021/acs.inorgchem.8b03024Zhuk N. A., Krzhizhanovskaya M. G., Belyy V. A., et al. High temperature crystal chemistry of α-, β-, and γ-BiNbO4 polymorphs / Inorg. Chem. 2019. Vol. 58. P. 1518 – 1525. DOI: 10.1021/acs.inorgchem.8b03024Parshukova K. N., Sekushin N. A., Makeev B. A., et al. Synthesis and dielectric properties, XPS spectroscopy study of high entropy pyrochlore / Lett. Mater. 2022. Vol. 12. P. 469 – 474. DOI: 10.22226/2410-3535-2022-4-469-474Parshukova K. N., Sekushin N. A., Makeev B. A., et al. Synthesis and dielectric properties, XPS spectroscopy study of high entropy pyrochlore / Lett. Mater. 2022. Vol. 12. P. 469 – 474. DOI: 10.22226/2410-3535-2022-4-469-474Shannon R. D. Revised effective ionic radii and systematic studies of interatomic distances in halides and chalcogenides / Acta Crystallogr. Sect. A: Found. Adv. 1976. Vol. 32. P. 751 – 767. DOI: 10.1107/s0567739476001551Shannon R. D. Revised effective ionic radii and systematic studies of interatomic distances in halides and chalcogenides / Acta Crystallogr. Sect. A: Found. Adv. 1976. Vol. 32. P. 751 – 767. DOI: 10.1107/s0567739476001551Hassel M., Freund H.-J. High Resolution XPS Study of a Thin CoO (111) Film Grown on Co (0001) / Surface Sci. Spectra. 1996. Vol. 4. P. 273 – 278. DOI: 10.1116/1.1247797Hassel M., Freund H.-J. High Resolution XPS Study of a Thin CoO (111) Film Grown on Co (0001) / Surface Sci. Spectra. 1996. Vol. 4. P. 273 – 278. DOI: 10.1116/1.1247797Grissa R., Martinez H., Cotte S., et al. Thorough XPS analyses on overlithiated manganese spinel cycled around the 3V plateau / Appl. Surface Sci. 2017. Vol. 411. P. 449 – 456. DOI: 10.1016/j.apsusc.2017.03.205Grissa R., Martinez H., Cotte S., et al. Thorough XPS analyses on overlithiated manganese spinel cycled around the 3V plateau / Appl. Surface Sci. 2017. Vol. 411. P. 449 – 456. DOI: 10.1016/j.apsusc.2017.03.205Stranick M. A. Mn2O3 by XPS / Surface Sci. Spectra. 1999. Vol. 6. P. 39 – 46. DOI: 10.1116/1.1247889Stranick M. A. Mn2O3 by XPS / Surface Sci. Spectra. 1999. Vol. 6. P. 39 – 46. DOI: 10.1116/1.1247889Gri F., Bigiani L., Gasparotto A., et al. XPS investigation of F doped MnO2 nanosystems fabricated by plasma assisted-CVD / Surface Sci. Spectra. 2018. Vol. 25. Art. 024004. DOI: 10.1116/1.5048908Gri F., Bigiani L., Gasparotto A., et al. XPS investigation of F doped MnO2 nanosystems fabricated by plasma assisted-CVD / Surface Sci. Spectra. 2018. Vol. 25. Art. 024004. DOI: 10.1116/1.5048908Bullen H. A., Garrett S. J. CrO2 by XPS: comparison of CrO2 powder to CrO2 films on TiO2 (110) single crystal surfaces / Surface Sci. Spectra. 2001. Vol. 8. P. 225. DOI: 10.1116/11.20020308Bullen H. A., Garrett S. J. CrO2 by XPS: comparison of CrO2 powder to CrO2 films on TiO2 (110) single crystal surfaces / Surface Sci. Spectra. 2001. Vol. 8. P. 225. DOI: 10.1116/11.20020308Jeong S.-Y., Lee J.-B., Na H., et al. Epitaxial growth of Cr2O3 thin film on Al2O3 (0001) substrate by radio frequency magnetron sputtering combined with rapid thermal annealing / Thin Solid Films. 2010. Vol. 518. P. 4813 – 4816. DOI: 10.1016/j.tsf.2010.01.046Jeong S.-Y., Lee J.-B., Na H., et al. Epitaxial growth of Cr2O3 thin film on Al2O3 (0001) substrate by radio frequency magnetron sputtering combined with rapid thermal annealing / Thin Solid Films. 2010. Vol. 518. P. 4813 – 4816. DOI: 10.1016/j.tsf.2010.01.046Jin Y. X., Li L. X., Dong H. L., et al. Structures, phase transformations, and dielectric properties of (1 – x)Bi2Zn2/3Nb4/3O7 – xBi1.5NiNb1.5O7 pyrochlore ceramics prepared by aqueous sol-gel method / J. Alloys Compounds. 2015. Vol. 622. P. 200 – 205. DOI: 10.1016/j.jallcom.2014.10.021Jin Y. X., Li L. X., Dong H. L., et al. Structures, phase transformations, and dielectric properties of (1 – x)Bi2Zn2/3Nb4/3O7 – xBi1.5NiNb1.5O7 pyrochlore ceramics prepared by aqueous sol-gel method / J. Alloys Compounds. 2015. Vol. 622. P. 200 – 205. DOI: 10.1016/j.jallcom.2014.10.021Ning P., Li L., Zhang X., et al. Enhanced tunability of Bi3/2MNb3/2O7 (M = Zn, Mg, Ni) thin films / Mater. Lett. 2012. Vol. 87. P. 5 – 8. DOI: 10.1016/j.matlet.2012.07.087Ning P., Li L., Zhang X., et al. Enhanced tunability of Bi3/2MNb3/2O7 (M = Zn, Mg, Ni) thin films / Mater. Lett. 2012. Vol. 87. P. 5 – 8. DOI: 10.1016/j.matlet.2012.07.087Valant M. Dielectric relaxations in Bi2O3-Nb2O5-NiO cubic pyrochlores / J. Am. Ceram. Soc. 2009. Vol. 92. P. 955 – 958. DOI: 10.1111/j.1551-2916.2009.02984.xValant M. Dielectric relaxations in Bi2O3-Nb2O5-NiO cubic pyrochlores / J. Am. Ceram. Soc. 2009. Vol. 92. P. 955 – 958. DOI: 10.1111/j.1551-2916.2009.02984.xCann D. P., Randall C. A., Shrout T. R. Investigation of the dielectric properties of bismuth pyrochlore / Solid State Comm. 1996. Vol. 7. P. 529 – 534. DOI: 10.1016/0038-1098(96)00012-9Cann D. P., Randall C. A., Shrout T. R. Investigation of the dielectric properties of bismuth pyrochlore / Solid State Comm. 1996. Vol. 7. P. 529 – 534. DOI: 10.1016/0038-1098(96)00012-9Zhang Y., Zhang Z., Zhu X., et al. Dielectric properties and microstructural characterization of cubic pyrochlored bismuth magnesium niobates / Appl. Phys. A. 2013. Vol. 115. P. 661 – 666. DOI: 10.1007/s00339-013-7843-8Zhang Y., Zhang Z., Zhu X., et al. Dielectric properties and microstructural characterization of cubic pyrochlored bismuth magnesium niobates / Appl. Phys. A. 2013. Vol. 115. P. 661 – 666. DOI: 10.1007/s00339-013-7843-8Osman R., Masó N., West A. Bismuth zinc niobate pyrochlore, a relaxor like non-ferroelectric / J. Am. Ceram. Soc. 2011. Vol. 95. P. 296 – 302.Osman R., Masó N., West A. Bismuth zinc niobate pyrochlore, a relaxor like non-ferroelectric / J. Am. Ceram. Soc. 2011. Vol. 95. P. 296 – 302.Zhuk N. A., Krzhizhanovskaya M. G., Koroleva A. V., et al. Thermal expansion, xps spectra, and structural and electrical properties of a new Bi2NiTa2O9 pyrochlore / Inorg. Chem. 2021. Vol. 60. P. 4924 – 4934. DOI: 10.1021/acs.inorgchem.1c00007Zhuk N. A., Krzhizhanovskaya M. G., Koroleva A. V., et al. Thermal expansion, xps spectra, and structural and electrical properties of a new Bi2NiTa2O9 pyrochlore / Inorg. Chem. 2021. Vol. 60. P. 4924 – 4934. DOI: 10.1021/acs.inorgchem.1c00007Lasia A. Electrochemical impedance spectroscopy and its applications. — New York: Springer Science + Business Media, 2014. — 369 p. DOI: 10.1007/978-1-4614-8933-7Lasia A. Electrochemical impedance spectroscopy and its applications. — New York: Springer Science + Business Media, 2014. — 369 p. DOI: 10.1007/978-1-4614-8933-7

The authors declare that there are no conflicts of interest present.