Pure and superstoichiometric modified by 2 wt.%Bi_(2)O_(3) and 2 wt.%manganese oxide(Mn_(2)O_(3))ceramic samples of the binary system 0.71BiFeO_(3)-0.29BaTiO_(3) were fabricated using conventional ceramic technology b...Pure and superstoichiometric modified by 2 wt.%Bi_(2)O_(3) and 2 wt.%manganese oxide(Mn_(2)O_(3))ceramic samples of the binary system 0.71BiFeO_(3)-0.29BaTiO_(3) were fabricated using conventional ceramic technology by double solid-phase synthesis with following sintering.Mechanical activation of synthesized powders was carried out at the stage of manufacturing press powders prepared for sintering.X-ray analysis at room temperature showed that all studied ceramics have pseudo-cubic symmetry.Grain morphology,dielectric and piezoelectric properties of selected solid solutions were investigated.The modification increased the homogeneity of the material,dielectric constant and piezomodulus d_(33) and also resulted in a decrease in the dielectric loss tangent.The highest piezoelectric coefficient d_(33)=105 pC/N was obtained.Dielectric characteristics of ceramics revealed feroelectric relaxor behavior and region of diffuse phase transition from the paraelectric to ferroelectric phase in the temperature range of 740-770 K.展开更多
By X-ray diffraction and dielectric spectroscopy,the crystal structure,phase composition,and properties of Sr_(0.6)Ba_(0.4)Nb_(2)O_(6)/Ba_(2)NdFeNb_(4)O_(15)/Sr_(0.6)Ba_(0.4)Nb_(2)/Ba_(2)NdFeNb_(4)O_(15)/SrRuO_(3)/MgO...By X-ray diffraction and dielectric spectroscopy,the crystal structure,phase composition,and properties of Sr_(0.6)Ba_(0.4)Nb_(2)O_(6)/Ba_(2)NdFeNb_(4)O_(15)/Sr_(0.6)Ba_(0.4)Nb_(2)/Ba_(2)NdFeNb_(4)O_(15)/SrRuO_(3)/MgO and Ba_(2)NdFeNb_(4)O_(15)/Sr_(0.6)Ba_(0.4)Nb_(2)O_(6)/Sr_(0.6)Ba_(0.4)-Nb_(2)O/SrRuOg/MgO multilayer heterostructures were studied.The heterostructures were manufactured under identical conditions but differing in the layer deposition sequence.It is shown that the orientation domains are formed in each Ba_(2)NdFeNb_(4)O_(15)(BNFN)and Sr_(0.6)Ba_(0.4)Nb_(2)O(SBN)layers.BNFN and SBN layers have tetragonal unit cells with tensile out-of-plane strain and compression in-plane strain.At T=-100...100℃both heterostructures are characterized by fairly high relative permittivity values.The reasons for the revealed regularities are discussed.展开更多
This paper is focused on the comparison of the results of various approximation models describing the frequency dependences of the dielectric constanε'/ε_(0)(f)andε"/ε_(0)(f),the tangent of the loss angle...This paper is focused on the comparison of the results of various approximation models describing the frequency dependences of the dielectric constanε'/ε_(0)(f)andε"/ε_(0)(f),the tangent of the loss angle tgδ(f)T and the electrical conductivityγ'(f)T andγ"(f)T of nonlinear dielectrics.The classic ferroelectric material of the PZT system with x=0.50 was chosen as the object of study.Based on the analysis of temperature-frequency dependences of the“empirical”parametersαandβ,a regularity has been revealed that allows them to be calculated.A new relationship has been established through the parameterα,which allows to relate the temperature and frequency dependences of the complex electrical conductivity asω→∞and asω→0 in the Havriliak-Negami approximation models and in the new model for the description of the complex electrical conductivityγ*.It is shown thatαis a parameter of the temperature-frequency distribution of dielectric losses.Using the obtained expressions,a new theoretical description of experimental spectra having a relaxation character was proposed.It has been proven that the use of the new model makes it possible to accurately describe the set of studied spectra,including the high and low frequencies,in the frequency range from 10^(-3) to 10^(8) Hz.展开更多
This work presents the results of study of the electrophysical properties of composite polymer ceramics(1−x)[KNN-LTSN]-xPVDF at x=25 vol.%and x=50 vol.%in the temperature range of T=20-160℃and frequency range of f=2&...This work presents the results of study of the electrophysical properties of composite polymer ceramics(1−x)[KNN-LTSN]-xPVDF at x=25 vol.%and x=50 vol.%in the temperature range of T=20-160℃and frequency range of f=2×10^(1)-2×10^(6)Hz.The concentration dependence of piezomodules of the studied materials has been analyzed as a function of temperature.X-ray measurements have also been carried out.A model of description of revealed dielectric parameters dispersion in the material is presented.The nonclassical modified Havriliak-Negami model written for complex electrical conductivity has been used to describe the temperature-frequency properties.It is shown that the dielectric spectra of the studied composites include three relaxation processes in the temperature ranges of 40-80℃,80-120℃and 120-150℃,which were confirmed by the dynamics of changes in the dependences of g′(f),tgδ(f),M′(f),M″(f)and M″(M′).All three processes are almost exactly described by this model and well correlated with the studies by other researchers of the composites based on PVDF.The results of this work show that the use of such experimental model is suitable for describing the complex dielectric spectra of any nonlinear dielectrics including composite materials.展开更多
The solid solutions of the(1-x)Na_(0.5)Bi_(0.5)TiO_(3-x)Na_(0.5)K_(0.5)NbO_(3) system were produced by the conventional ceramic technology using mechanical activation of the synthesized product.It was found that in th...The solid solutions of the(1-x)Na_(0.5)Bi_(0.5)TiO_(3-x)Na_(0.5)K_(0.5)NbO_(3) system were produced by the conventional ceramic technology using mechanical activation of the synthesized product.It was found that in the(1-x)Na_(0.5)Bi_(0.5)TiO_(3-x)Na_(0.5)K_(0.5)NbO_(3) system at room temperature,a number of morphotropic phase transitions occur:rhombohedral!cubic!tetragonal!monoclinic phases.The introduction of a small amount of Na_(0.5)K_(0.5)NbO_(3) leads to an increase in the temperature stability of the dielectric properties of ceramics.A change in the relaxor properties of the solid solutions of the(1-x)Na_(0.5)Bi_(0.5)TiO_(3-x)Na_(0.5)K_(0.5)NbO_(3) system was shown.The increase in energy density and energy efficiency was found at additive 10 mol.%of Na_(0.5)K_(0.5)NbO_(3).展开更多
Ceramics of quasi-binary concentration section(x=0.50,0.1≤y≤0.2,Δy=0.025)of the ternary solid solution system(1−x−y)BiFeO_(3)-xPbFe_(0.5)Nb_(0.5)O_(3)-yPbTiO_(3)were prepared by the conventional solid-phase reactio...Ceramics of quasi-binary concentration section(x=0.50,0.1≤y≤0.2,Δy=0.025)of the ternary solid solution system(1−x−y)BiFeO_(3)-xPbFe_(0.5)Nb_(0.5)O_(3)-yPbTiO_(3)were prepared by the conventional solid-phase reaction method.By using X-ray diffraction technique,the phase diagram of the system was constructed,which was shown to contain the regions of cubic and tetragonal symmetry and the morphotropic phase boundary between them.Grain morphology,dielectric and piezoelectric properties of the selected solid solutions were investigated.The highest piezoelectric coefficient d_(33)=260 pC/N was obtained.Dielectric characteristics of ceramics revealed ferroelectric relaxor behavior,a region of diffuse phase transition from the paraelectric to ferroelectric phase in the temperature range of 350-500 K.展开更多
The properties studying results of ceramics based on strontium,calcium and sodium niobates,which vary from the conditions of synthesis,sintering,and mechanical processing,are presented.The evolution of the grain struc...The properties studying results of ceramics based on strontium,calcium and sodium niobates,which vary from the conditions of synthesis,sintering,and mechanical processing,are presented.The evolution of the grain structure of objects is traced depending on their phase filling during concentration changes in the composition and thermodynamic prehistory(preparation conditions).展开更多
This work presents the results of studying the electrophysical properties of the YCu_(0.15)Mn_(0.85)O_(3)solid solution in the range of temperatures of T=26-400°C and frequency range of f=102-105 Hz.A model descr...This work presents the results of studying the electrophysical properties of the YCu_(0.15)Mn_(0.85)O_(3)solid solution in the range of temperatures of T=26-400°C and frequency range of f=102-105 Hz.A model description of the revealed dispersion of dielectric parameters in the material is made.The nonclassical modified Havriliak-Negami model written for complex electrical conduc-tivity was used as an approximation model.It is shown that the application of this model almost exactly describes the frequency behavior of the dielectric constantε′/ε0(f),the dielectric loss tangent tgδ(f)as well as the real and imaginary parts of complex conductivityγ′(f)andγ′′(f).The results of this work are an important step in identifying the opportunities and understanding the applications of this model.展开更多
基金financial support of the Ministry of Science and Higher Education of the Russian Federation(State task in the field of scientific activity.Project No.FENW-2023-0010/GZ0110/23-11-IF)。
文摘Pure and superstoichiometric modified by 2 wt.%Bi_(2)O_(3) and 2 wt.%manganese oxide(Mn_(2)O_(3))ceramic samples of the binary system 0.71BiFeO_(3)-0.29BaTiO_(3) were fabricated using conventional ceramic technology by double solid-phase synthesis with following sintering.Mechanical activation of synthesized powders was carried out at the stage of manufacturing press powders prepared for sintering.X-ray analysis at room temperature showed that all studied ceramics have pseudo-cubic symmetry.Grain morphology,dielectric and piezoelectric properties of selected solid solutions were investigated.The modification increased the homogeneity of the material,dielectric constant and piezomodulus d_(33) and also resulted in a decrease in the dielectric loss tangent.The highest piezoelectric coefficient d_(33)=105 pC/N was obtained.Dielectric characteristics of ceramics revealed feroelectric relaxor behavior and region of diffuse phase transition from the paraelectric to ferroelectric phase in the temperature range of 740-770 K.
基金supported by the Ministry of Science and Higher Education of the Russian Federation in the framework of the state task in the field of scientific activity,Grant No.FENW-2022-0001prepared as part of a government assignment Southern Scientific Centre of the Russian Academy of Sciences under Project Number 122020100294-9(FMRE-2025-0051).
文摘By X-ray diffraction and dielectric spectroscopy,the crystal structure,phase composition,and properties of Sr_(0.6)Ba_(0.4)Nb_(2)O_(6)/Ba_(2)NdFeNb_(4)O_(15)/Sr_(0.6)Ba_(0.4)Nb_(2)/Ba_(2)NdFeNb_(4)O_(15)/SrRuO_(3)/MgO and Ba_(2)NdFeNb_(4)O_(15)/Sr_(0.6)Ba_(0.4)Nb_(2)O_(6)/Sr_(0.6)Ba_(0.4)-Nb_(2)O/SrRuOg/MgO multilayer heterostructures were studied.The heterostructures were manufactured under identical conditions but differing in the layer deposition sequence.It is shown that the orientation domains are formed in each Ba_(2)NdFeNb_(4)O_(15)(BNFN)and Sr_(0.6)Ba_(0.4)Nb_(2)O(SBN)layers.BNFN and SBN layers have tetragonal unit cells with tensile out-of-plane strain and compression in-plane strain.At T=-100...100℃both heterostructures are characterized by fairly high relative permittivity values.The reasons for the revealed regularities are discussed.
基金Authors express gratitude to Doctor of Science(Physics and Mathematics)Professor L.A.Reznichenko.The work is performed as part of the project of the SSC RAS State Order(projects 01201354240 and 01201354247)with the use of equipment of the Centers for Collective Use“Electromagnetic,Electromechanical and Thermal Properties of Solids”,Research Institute of Physics,Southern Federal University and“Integrated Centre of scientific-technological equipment SSC RAS(research,development,approval)”Southern Scientific Centre of RAS(No.501994)and also with the assistance of Ministry of Science and Higher Education of the Russian Federation(State assignment in the field of scientific activity,Southern Federal University,2020)Moreover,reported study was funded by RFBR,project number 19-05-50099.
文摘This paper is focused on the comparison of the results of various approximation models describing the frequency dependences of the dielectric constanε'/ε_(0)(f)andε"/ε_(0)(f),the tangent of the loss angle tgδ(f)T and the electrical conductivityγ'(f)T andγ"(f)T of nonlinear dielectrics.The classic ferroelectric material of the PZT system with x=0.50 was chosen as the object of study.Based on the analysis of temperature-frequency dependences of the“empirical”parametersαandβ,a regularity has been revealed that allows them to be calculated.A new relationship has been established through the parameterα,which allows to relate the temperature and frequency dependences of the complex electrical conductivity asω→∞and asω→0 in the Havriliak-Negami approximation models and in the new model for the description of the complex electrical conductivityγ*.It is shown thatαis a parameter of the temperature-frequency distribution of dielectric losses.Using the obtained expressions,a new theoretical description of experimental spectra having a relaxation character was proposed.It has been proven that the use of the new model makes it possible to accurately describe the set of studied spectra,including the high and low frequencies,in the frequency range from 10^(-3) to 10^(8) Hz.
基金financially supported by the Ministry of Science and Higher Education of the Russian Federation:State Task in the Field of Scientific Activity,Scientific Project No.0852-2020-0032(BAZ0110/20-3-07IF)with the use of equipment of the Center for Collective Use“Integrated Centre of Scientific-Technological Equipment SSC RAS(Research,Development,Approval)”,Southern Scientific Centre of RAS(No.501994).The dielectric measurements were performed using the equipment of the Shared Research Facility Centre of SFedU,Research Institute of Physics.
文摘This work presents the results of study of the electrophysical properties of composite polymer ceramics(1−x)[KNN-LTSN]-xPVDF at x=25 vol.%and x=50 vol.%in the temperature range of T=20-160℃and frequency range of f=2×10^(1)-2×10^(6)Hz.The concentration dependence of piezomodules of the studied materials has been analyzed as a function of temperature.X-ray measurements have also been carried out.A model of description of revealed dielectric parameters dispersion in the material is presented.The nonclassical modified Havriliak-Negami model written for complex electrical conductivity has been used to describe the temperature-frequency properties.It is shown that the dielectric spectra of the studied composites include three relaxation processes in the temperature ranges of 40-80℃,80-120℃and 120-150℃,which were confirmed by the dynamics of changes in the dependences of g′(f),tgδ(f),M′(f),M″(f)and M″(M′).All three processes are almost exactly described by this model and well correlated with the studies by other researchers of the composites based on PVDF.The results of this work show that the use of such experimental model is suitable for describing the complex dielectric spectra of any nonlinear dielectrics including composite materials.
基金support of the Ministry of Science and Higher Education of the Federation(State task in the field of scientific activity in 2023)Project No.FENW-2023-0010/(GZ0110/23-11-IF).
文摘The solid solutions of the(1-x)Na_(0.5)Bi_(0.5)TiO_(3-x)Na_(0.5)K_(0.5)NbO_(3) system were produced by the conventional ceramic technology using mechanical activation of the synthesized product.It was found that in the(1-x)Na_(0.5)Bi_(0.5)TiO_(3-x)Na_(0.5)K_(0.5)NbO_(3) system at room temperature,a number of morphotropic phase transitions occur:rhombohedral!cubic!tetragonal!monoclinic phases.The introduction of a small amount of Na_(0.5)K_(0.5)NbO_(3) leads to an increase in the temperature stability of the dielectric properties of ceramics.A change in the relaxor properties of the solid solutions of the(1-x)Na_(0.5)Bi_(0.5)TiO_(3-x)Na_(0.5)K_(0.5)NbO_(3) system was shown.The increase in energy density and energy efficiency was found at additive 10 mol.%of Na_(0.5)K_(0.5)NbO_(3).
基金The study was carried out with the financial support of the Ministry of Science and Higher Education of the Russian Federation(State task in the field of scientific activity,scientific project No.0852-2020-0032)(BAZ0110/20-3-07IF)Work was performed using the equipment of the Center for Collective Use“Electromagnetic,Electromechanical and Thermal Properties of Solids”,Research Institute of Physics,Southern Federal University and Center for Collective Use of the Southern Scientific Center of the Russian Academy of Science(Rostov-on-Don,Russia).
文摘Ceramics of quasi-binary concentration section(x=0.50,0.1≤y≤0.2,Δy=0.025)of the ternary solid solution system(1−x−y)BiFeO_(3)-xPbFe_(0.5)Nb_(0.5)O_(3)-yPbTiO_(3)were prepared by the conventional solid-phase reaction method.By using X-ray diffraction technique,the phase diagram of the system was constructed,which was shown to contain the regions of cubic and tetragonal symmetry and the morphotropic phase boundary between them.Grain morphology,dielectric and piezoelectric properties of the selected solid solutions were investigated.The highest piezoelectric coefficient d_(33)=260 pC/N was obtained.Dielectric characteristics of ceramics revealed ferroelectric relaxor behavior,a region of diffuse phase transition from the paraelectric to ferroelectric phase in the temperature range of 350-500 K.
基金The study was carried out with the financial support of the Ministry of Science and Higher Education of the Russian Federation(State task in the field of scientific activity,sci-entific project No.0852-2020-0032),(BA30110/20-3-07IF).
文摘The properties studying results of ceramics based on strontium,calcium and sodium niobates,which vary from the conditions of synthesis,sintering,and mechanical processing,are presented.The evolution of the grain structure of objects is traced depending on their phase filling during concentration changes in the composition and thermodynamic prehistory(preparation conditions).
基金The work was conducted within the State assignment of SSC RAS(Project Nos.01201354240 and 01201354247).
文摘This work presents the results of studying the electrophysical properties of the YCu_(0.15)Mn_(0.85)O_(3)solid solution in the range of temperatures of T=26-400°C and frequency range of f=102-105 Hz.A model description of the revealed dispersion of dielectric parameters in the material is made.The nonclassical modified Havriliak-Negami model written for complex electrical conduc-tivity was used as an approximation model.It is shown that the application of this model almost exactly describes the frequency behavior of the dielectric constantε′/ε0(f),the dielectric loss tangent tgδ(f)as well as the real and imaginary parts of complex conductivityγ′(f)andγ′′(f).The results of this work are an important step in identifying the opportunities and understanding the applications of this model.
