Dielectric permittivity was studied in ceramics of relaxor ferroelectric bismuth-sodium titanate Na0.5Bi0.5TiO3. The measurements were performed on as sintered and heat treated in vacuum samples. The diffuse dielectric anomalies associated with the structural phase transitions were observed in as sintered samples. The intense peak of permittivity (εmax ∼ 104) appeared after heat treating in vacuum. The anomaly of ε(T) was contributed by slow polarization processes (f < 10 kHz) and was non-stable, vanishing on heating in air up to ∼ 800 K. Temperature and frequency dependencies of ε were described by using Cole-Cole model with accounting thermally stimulated decay of the non-stable polarization. It is supposed that the dielectric anomaly is determined by space charge polarization mechanism. Oxygen vacancies VO•• and electrons localized on titanium ions Ti'Ti are assumed to be responsible for the phenomenon observed.
{"title":"Dielectric relaxation induced by oxygen vacancies in Na0.5Bi0.5TiO3 ceramics","authors":"V. Sidak, M. Trubitsyn, T. Panchenko","doi":"10.5488/CMP.25.43705","DOIUrl":"https://doi.org/10.5488/CMP.25.43705","url":null,"abstract":"Dielectric permittivity was studied in ceramics of relaxor ferroelectric bismuth-sodium titanate Na0.5Bi0.5TiO3. The measurements were performed on as sintered and heat treated in vacuum samples. The diffuse dielectric anomalies associated with the structural phase transitions were observed in as sintered samples. The intense peak of permittivity (εmax ∼ 104) appeared after heat treating in vacuum. The anomaly of ε(T) was contributed by slow polarization processes (f < 10 kHz) and was non-stable, vanishing on heating in air up to ∼ 800 K. Temperature and frequency dependencies of ε were described by using Cole-Cole model with accounting thermally stimulated decay of the non-stable polarization. It is supposed that the dielectric anomaly is determined by space charge polarization mechanism. Oxygen vacancies VO•• and electrons localized on titanium ions Ti'Ti are assumed to be responsible for the phenomenon observed.","PeriodicalId":10528,"journal":{"name":"Condensed Matter Physics","volume":"64 1","pages":""},"PeriodicalIF":0.6,"publicationDate":"2023-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84740163","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Using the previously developed model we revisit the problem of the electric field induced polarization rotation in antiferroelectric crystals of squaric acid. We test an alternative set of the model parameters, according to which the dipole moments associated with the H2C4O4 groups are assumed to be parallel to the diagonals of the ac plane. The T-E phase diagrams and the polarization curves P(E) for the fields directed along the a axis and along one of the diagonals are considered. Comparison of the theoretical results with the newly published experimental data confirm the validity of the model. The calculations reveal no apparent advantage of the new set of the parameters over the previously used set.
{"title":"Electric field induced polarization rotation in squaric acid crystals revisited","authors":"A. Moina","doi":"10.5488/CMP.25.43710","DOIUrl":"https://doi.org/10.5488/CMP.25.43710","url":null,"abstract":"Using the previously developed model we revisit the problem of the electric field induced polarization rotation in antiferroelectric crystals of squaric acid. We test an alternative set of the model parameters, according to which the dipole moments associated with the H2C4O4 groups are assumed to be parallel to the diagonals of the ac plane. The T-E phase diagrams and the polarization curves P(E) for the fields directed along the a axis and along one of the diagonals are considered. Comparison of the theoretical results with the newly published experimental data confirm the validity of the model. The calculations reveal no apparent advantage of the new set of the parameters over the previously used set.","PeriodicalId":10528,"journal":{"name":"Condensed Matter Physics","volume":"9 1","pages":""},"PeriodicalIF":0.6,"publicationDate":"2023-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86353693","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
To investigate the caloric effects in the CsH2PO4 ferroelectric, a modified pseudospin model of this crystal is used, which takes into account the dependence of the parameters of interaction between pseudospins on lattice strains. The model also takes into account the dependence of the effective dipole moment of a pseudospin on the order parameter. In the two-particle cluster approximation, the influence of the longitudinal electric field and hydrostatic pressure on the molar entropy of the crystal was studied. The electrocaloric and barocaloric effects were studied. The calculated electrocaloric temperature change is about 1 K; it can change its sign under the influence of hydrostatic pressure. Barocaloric temperature change is about -0.5 K; lattice anharmonicities were not taken into account in its calculations.
{"title":"Electrocaloric and barocaloric effects in CsH2PO4 ferroelectric","authors":"A. Vdovych, R. Levitskii, I. R. Zachek","doi":"10.5488/CMP.25.43711","DOIUrl":"https://doi.org/10.5488/CMP.25.43711","url":null,"abstract":"To investigate the caloric effects in the CsH2PO4 ferroelectric, a modified pseudospin model of this crystal is used, which takes into account the dependence of the parameters of interaction between pseudospins on lattice strains. The model also takes into account the dependence of the effective dipole moment of a pseudospin on the order parameter. In the two-particle cluster approximation, the influence of the longitudinal electric field and hydrostatic pressure on the molar entropy of the crystal was studied. The electrocaloric and barocaloric effects were studied. The calculated electrocaloric temperature change is about 1 K; it can change its sign under the influence of hydrostatic pressure. Barocaloric temperature change is about -0.5 K; lattice anharmonicities were not taken into account in its calculations.","PeriodicalId":10528,"journal":{"name":"Condensed Matter Physics","volume":"1 1","pages":""},"PeriodicalIF":0.6,"publicationDate":"2023-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82979550","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We have studied the composition dependence of density of liquid water-DMSO mixtures at different temperatures by using the isobaric-isothermal (NPT) molecular dynamics computer simulations. The non-polarizable semi-flexible, P1 and P2 models for the DMSO molecule combined with the TIP4P-2005 water model are considered. The excess mixing volume and the apparent molar volumes of the species are reported. We have established that the P1-TIP4P-2005 model for the mixture provides a very good description of the location of the minimum of apparent molar volume for DMSO species indicating the anomaly. Most important is that the temperature interval where the hydrophobic effect exists, is correctly captured with this modelling, in contrast to the P2-TIP4P-2005 model.
{"title":"Apparent molar volume anomaly in water-dimethyl sulfoxide liquid mixtures. Molecular dynamics computer simulations","authors":"M. Aguilar, H. Domínguez, O. Pizio","doi":"10.5488/CMP.25.44201","DOIUrl":"https://doi.org/10.5488/CMP.25.44201","url":null,"abstract":"We have studied the composition dependence of density of liquid water-DMSO mixtures at different temperatures by using the isobaric-isothermal (NPT) molecular dynamics computer simulations. The non-polarizable semi-flexible, P1 and P2 models for the DMSO molecule combined with the TIP4P-2005 water model are considered. The excess mixing volume and the apparent molar volumes of the species are reported. We have established that the P1-TIP4P-2005 model for the mixture provides a very good description of the location of the minimum of apparent molar volume for DMSO species indicating the anomaly. Most important is that the temperature interval where the hydrophobic effect exists, is correctly captured with this modelling, in contrast to the P2-TIP4P-2005 model.","PeriodicalId":10528,"journal":{"name":"Condensed Matter Physics","volume":"10 1","pages":""},"PeriodicalIF":0.6,"publicationDate":"2023-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79273032","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The review covers the theoretical and experimental results obtained in the recent years by the scientists with the help of comprehensive investigation of nanoferroics and multiferroics. The main attention will be paid to spontaneous flexoeffects and reentrant phase in nanoferroics as well as to a recently discovered giant magnetoelectric effect in multiferroics.
{"title":"New trends in the nanophysics of ferroics, relaxors and multiferroics","authors":"M. Glinchuk, L. Yurchenko, E. Eliseev","doi":"10.5488/CMP.25.42201","DOIUrl":"https://doi.org/10.5488/CMP.25.42201","url":null,"abstract":"The review covers the theoretical and experimental results obtained in the recent years by the scientists with the help of comprehensive investigation of nanoferroics and multiferroics. The main attention will be paid to spontaneous flexoeffects and reentrant phase in nanoferroics as well as to a recently discovered giant magnetoelectric effect in multiferroics.","PeriodicalId":10528,"journal":{"name":"Condensed Matter Physics","volume":"159 1","pages":""},"PeriodicalIF":0.6,"publicationDate":"2023-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72983250","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
V. Pashchenko, O. Bludov, D. Baltrunas, K. Mažeika, S. Motria, K. Glukhov, Y. Vysochanskii
The experimental studies of the paramagnetic-antiferromagnetic phase transition through Mössbauer spectroscopy and measurements of temperature and field dependencies of magnetic susceptibility in the layered Cu0.15Fe0.85PS3 crystal are presented. The peculiar behavior of the magnetization - field dependence at low-temperature region gives evidence of a weak ferromagnetism in the studied alloy. By the ab initio simulation of electronic and spin subsystems, in the framework of electron density functional theory, the peculiarities of spin ordering at low temperature as well as changes in interatomic interactions in the vicinity of the Cu substitutional atoms are analyzed. The calculated components of the electric field gradient tensor and asymmetry parameter for Fe ions are close to the ones found from Mössbauer spectra values. The Mulliken populations show that the main contribution to the ferromagnetic spin density is originated from 3d-copper and 3p-sulfur orbitals. The estimated total magnetic moment of the unit cell (8.543 emu/mol) is in reasonable agreement with the measured experimental value of ∼9 emu/mol.
{"title":"The antiferromagnetic phase transition in the layered Cu0.15Fe0.85PS3 semiconductor: experiment and DFT modelling","authors":"V. Pashchenko, O. Bludov, D. Baltrunas, K. Mažeika, S. Motria, K. Glukhov, Y. Vysochanskii","doi":"10.5488/CMP.25.43701","DOIUrl":"https://doi.org/10.5488/CMP.25.43701","url":null,"abstract":"The experimental studies of the paramagnetic-antiferromagnetic phase transition through Mössbauer spectroscopy and measurements of temperature and field dependencies of magnetic susceptibility in the layered Cu0.15Fe0.85PS3 crystal are presented. The peculiar behavior of the magnetization - field dependence at low-temperature region gives evidence of a weak ferromagnetism in the studied alloy. By the ab initio simulation of electronic and spin subsystems, in the framework of electron density functional theory, the peculiarities of spin ordering at low temperature as well as changes in interatomic interactions in the vicinity of the Cu substitutional atoms are analyzed. The calculated components of the electric field gradient tensor and asymmetry parameter for Fe ions are close to the ones found from Mössbauer spectra values. The Mulliken populations show that the main contribution to the ferromagnetic spin density is originated from 3d-copper and 3p-sulfur orbitals. The estimated total magnetic moment of the unit cell (8.543 emu/mol) is in reasonable agreement with the measured experimental value of ∼9 emu/mol.","PeriodicalId":10528,"journal":{"name":"Condensed Matter Physics","volume":"8 1","pages":""},"PeriodicalIF":0.6,"publicationDate":"2023-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74255588","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this work we show that the critical exponents of the order parameter (CEOPs) of diffuse ferroelectric phase transitions (DFEPTs) occurring in lead germanate-based crystals can be determined using experimental temperature dependences of their optical rotation. We also describe the approach that suggests dividing a crystal sample into many homogeneous unit cells, each of which is characterized by a non-diffuse phase transition with a specific local Curie temperature. Using this approach, the CEOPs have been determined for the pure Pb5Ge3O11 crystals, the solid solutions Pb5(Ge1-xSix)3O11 (x = 0.03, 0.05, 0.10, 0.20, 0.40) and (Pb1-xBax)5Ge3O11 (x = 0.02, 0.05), and the doped crystals Pb5Ge3O11:Li3+ (0.005 wt.), Pb5Ge3O11:La3+ (0.02 wt.), Pb5Ge3O11:Eu3+ (0.021 wt.), Pb5Ge3O11:Li3+, Bi3+ (0.152 wt.) and Pb5Ge3O11:Cu2+ (0.14 wt.). Comparison of our approach with the other techniques used for determining the Curie temperatures and the CEOPs of DFEPTs testifies to its essential advantages.
{"title":"Critical exponents of the order parameter of diffuse ferroelectric phase transitions in the solid solutions based on lead germanate: studies of optical rotation","authors":"D. Adamenko, R. Vlokh","doi":"10.5488/CMP.25.43703","DOIUrl":"https://doi.org/10.5488/CMP.25.43703","url":null,"abstract":"In this work we show that the critical exponents of the order parameter (CEOPs) of diffuse ferroelectric phase transitions (DFEPTs) occurring in lead germanate-based crystals can be determined using experimental temperature dependences of their optical rotation. We also describe the approach that suggests dividing a crystal sample into many homogeneous unit cells, each of which is characterized by a non-diffuse phase transition with a specific local Curie temperature. Using this approach, the CEOPs have been determined for the pure Pb5Ge3O11 crystals, the solid solutions Pb5(Ge1-xSix)3O11 (x = 0.03, 0.05, 0.10, 0.20, 0.40) and (Pb1-xBax)5Ge3O11 (x = 0.02, 0.05), and the doped crystals Pb5Ge3O11:Li3+ (0.005 wt.), Pb5Ge3O11:La3+ (0.02 wt.), Pb5Ge3O11:Eu3+ (0.021 wt.), Pb5Ge3O11:Li3+, Bi3+ (0.152 wt.) and Pb5Ge3O11:Cu2+ (0.14 wt.). Comparison of our approach with the other techniques used for determining the Curie temperatures and the CEOPs of DFEPTs testifies to its essential advantages.","PeriodicalId":10528,"journal":{"name":"Condensed Matter Physics","volume":"22 1","pages":""},"PeriodicalIF":0.6,"publicationDate":"2023-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74987610","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The barium sodium niobate (BNN) with tungsten-bronze structure is one of well-known optical crystals for electro-optic and nonlinear optic applications. This paper reviews the ferroelectric instability of BNN crystals. BNN is a uniaxial ferroelectric with a spontaneous polarization along the tetragonal c-axis. There is no report on the observation of an optical soft mode responsible for a ferroelectric phase transition. In the vicinity of the Curie temperature, TC = 560°C, an intense central peak (CP) related to the polarization fluctuations along the c-axis was observed by the broadband Brillouin scattering experiment. The relaxation time determined by the CP width shows the critical slowing down towards TC. This fact indicates that the ferroelectric instability of BNN is an order-disorder type.
{"title":"Broadband Brillouin scattering study of ferroelectric instability of barium sodium niobate","authors":"S. Kojima","doi":"10.5488/CMP.25.43702","DOIUrl":"https://doi.org/10.5488/CMP.25.43702","url":null,"abstract":"The barium sodium niobate (BNN) with tungsten-bronze structure is one of well-known optical crystals for electro-optic and nonlinear optic applications. This paper reviews the ferroelectric instability of BNN crystals. BNN is a uniaxial ferroelectric with a spontaneous polarization along the tetragonal c-axis. There is no report on the observation of an optical soft mode responsible for a ferroelectric phase transition. In the vicinity of the Curie temperature, TC = 560°C, an intense central peak (CP) related to the polarization fluctuations along the c-axis was observed by the broadband Brillouin scattering experiment. The relaxation time determined by the CP width shows the critical slowing down towards TC. This fact indicates that the ferroelectric instability of BNN is an order-disorder type.","PeriodicalId":10528,"journal":{"name":"Condensed Matter Physics","volume":"1 1","pages":""},"PeriodicalIF":0.6,"publicationDate":"2023-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89142405","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
It is our pleasure and honour to dedicate this Festschrift to Bertrand Berche on the occasion of his 60th birthday. Here, colleagues and friends pay tribute to Betrand's long lasting and highly valued work in the fields of statistical and condensed matter physics, complex systems, history of science, philosophy of science as well as interdisciplinary applications.
{"title":"Complexity and Collective Behaviour: Solids, Fields, and Data (dedicated to Bertrand Berche on his 60th birthday)","authors":"R. Folk, Y. Holovatch, R. Kenna, M. Krasnytska","doi":"10.5488/cmp.26.10101","DOIUrl":"https://doi.org/10.5488/cmp.26.10101","url":null,"abstract":"It is our pleasure and honour to dedicate this Festschrift to Bertrand Berche on the occasion of his 60th birthday. Here, colleagues and friends pay tribute to Betrand's long lasting and highly valued work in the fields of statistical and condensed matter physics, complex systems, history of science, philosophy of science as well as interdisciplinary applications.","PeriodicalId":10528,"journal":{"name":"Condensed Matter Physics","volume":"02 1","pages":""},"PeriodicalIF":0.6,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86519337","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：