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| 1 | Understanding X-ray absorption spectra by means of descriptors and machine learning algorithms显示文摘X-ray absorption near-edge structure(XANES)spectra are the fingerprint of the local atomic and electronic structures around the absorbing atom.However,the quantitative analysis of these spectra is not straightforward.Even with the most recent advances in this area,for a given spectrum,it is not clear a priori which structural parameters can be refined and how uncertainties should be estimated.Here,we present an alternative concept for the analysis of XANES spectra,which is based on machine learning algorithms and establishes the relationship between intuitive descriptors of spectra,such as edge position,intensities,positions,and curvatures of minima and maxima on the one hand,and those related to the local atomic and electronic structure which are the coordination numbers,bond distances and angles and oxidation state on the other hand.This approach overcoms the problem of the systematic difference between theoretical and experimental spectra.Furthermore,the numerical relations can be expressed in analytical formulas providing a simple and fast tool to extract structural parameters based on the spectral shape.The methodology was successfully applied to experimental data for the multicomponent Fe:SiO_(2)system and reference iron compounds,demonstrating the high prediction quality for both the theoretical validation sets and experimental data. | A.A.Guda S.A.Guda A.Martini A.N.Kravtsova A.Algasov A.Bugaev S.P.Kubrin L.V.Guda P.Šot J.A.van Bokhoven C.Copéret A.V.Soldatov | 2021 | npj Computational Materials2021，，1： | 0 |
| 2 | Mossbauer and magnetization studies of magnetic phase transitions in 0.5BiFeO_(3)-0.5NaNbO_(3)and 0.5LaFeO_(3)-0.5NaNbO_(3)solid solutions显示文摘0.5AFeO_(3)-0.5NaNbO_(3)(A=Bi,La)solid solution compositions were prepared using a solid phase reaction route from high-purity starting oxides.Mossbauer studies have shown that while for 0.5BiFeO_(3)-0.5NaNbO_(3)the magnetic phase transition temperature T_(M) value is about 150 K,for 0.5LaFeO_(3)-0.5NaNbO_(3),it is only≈25 K.This dramatic difference in T_(M) values seems to be due to additional contribution of the magnetic superexchange between Fe^(3+)ions via the empty 6p-states of Bi^(3+)ions to the overall superexchange. | S.I.Raevskaya S.P.Kubrin Jian Zhuang I.P.Raevski M.A.Malitskaya I.N.Zakharchenko M.S.Panchelyuga V.V.Titov | 2020 | Journal of Advanced Dielectrics2020，10，1： | 0 |
| 3 | Dielectric spectroscopy of solid solutions based on sodium-potassium-cadmium in the temperature range (10 ÷ 900) K显示文摘This paper studies the dielectric spectra of solid solutions(SS)of the system(1−x−y)NaNbO_(3)-xKNbO_(3)-yCdNb_(2)O_(6) y=0.075,x=0.05÷0.30 in the temperature range(10÷900)K.The formation of a local maximum was established in the interval(260÷300)K at small x values,which,as KNbO3 increases,is gradually blurred and becomes an inflection point.Detected in SS with x=0.05÷0.10,the shift of the maxima of dependencesε′/ε_(0)(T)andε″/ε_(0)(T),depending on the frequency of the electric field at the temperature ranges(300÷304)K and(258÷271)K,is not related to relaxation.This anomaly may indicate a crystallographic disorder to A and B positions.The conclusion is made about the expediency of using the obtained results for the development of functional ferroactive materials. | M.O.Moysa K.P.Andryushin A.V.Pavlenko S.P.Kubrin L.A.Reznichenko | 2022 | Journal of Advanced Dielectrics2022，12，4： | 0 |
| 4 | Dielectric properties of bismuth-containing pyrochlores:A comparative analysis显示文摘The comparative analysis of the dielectric properties of bismuth-containing pyrochlores with different manifestation of atomic order/disorder was carried out.We examined the dielectric properties(including behavior in electric fields)of two pyrochlore compounds:BZN(presumably a composition close to Bi_(1.5)Zn_(0.5)Nb_(1.5)O_(6.5))ceramics with chemical disorder in both A and B cation sublattices and Bi_(2)Ti_(2)O_(7)single crystal with fully chemical ordered structure.The fundamental differences between the dielectric properties of the BZN ceramics and Bi_(2)Ti_(2)O_(7)single crystal were shown.In particular,in the dielectric relaxation behavior(which cannot be described via Arrhenius law in the Bi_(2)Ti_(2)O_(7))or in the influence of the electric fields on the dielectric permittivity(split-ting of the field-cooled and zero-field-cooled behaviors was observed for Bi_(2)Ti_(2)O_(7)below estimated freezing temperature).The results of this study highlights the special role of Bi_(2)Ti_(2)O_(7)as a candidate material for studying aspects of geometric frustration related with pyrochlore structure in non-magnetic medium and specifies the future directions of research. | M.V.Talanov E.V.Glazunova V.I.Kozlov S.P.Kubrin A.A.Bush V.M.Talanov K.E.Kamentsev | 2022 | Journal of Advanced Dielectrics2022，12，2： | 0 |
| 5 | Chemical ordering and magnetic phase transitions in multiferroic BiFeO_(3)-AFe_(1/2)Sb_(1/2)O_(3)(A-Pb,Sr)solid solutions fabricated by a high-pressure显示文摘synthesisCeramic samples of BiFeO_(3)-based perovskite solid solutions with the highly ordered complex perovskites PbFe_(1/2)Sb_(1/2)O_(3)(PFS)and SrFe_(1/2)Sb_(1/2)O_(3)(SFS)were obtained using high-pressure synthesis at 4-6 GPa.Mössbauer studies revealed that BiFeO_(3)-SFS compositions are characterized by a larger compositional inhomogeneity as compared to BiFeO_(3)-PFS ones.In line with this result,concentration dependence of the magnetic phase transition temperature TN for BiFeO_(3)-SFS compositions is close to the TN(x)dependence for BiFeO_(3)solid solution with disordered perovskite PbFe_(1/2)Nb_(1/2)O_(3)(PFN).In contrast to this TN(x)dependence for BiFeO_(3)-PFS compositions nicely follows the theoretical TN(x)dependence calculated for the case of the ordered distribution of Fe3+and non-magnetic Sb^(5)+ions in the lattice(chemical ordering). | S.I.Raevskaya N.M.Olekhnovich A.V.Pushkarev Y.V.Radyush S.P.Kubrin V.V.Titov E.A.Artseva I.P.Raevski I.N.Zakharchenko C-C.Chou M.A.Malitskaya | 2022 | Journal of Advanced Dielectrics2022，12，1： | 0 |
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