Pub Date : 2004-06-01DOI: 10.1179/096797804225012864
P. Nandi, A. Garg, R. Singh, B. Chattoraj
Abstract The present study was carried out on the matrix composition of spinel forming high alumina castable to determine the effects of silica, magnesia particle size and temperature on spinel formation, the alumina content of the spinel formed, and associated physical characteristics at high temperature. It was found that an increase in silica content and use of finer magnesia helps to increase spinel formation. However to increase the alumina content of the spinel, increased temperature and magnesia particle size were more effective than an increased amount of silica. Furthermore the permanent linear change and porosity of the matrix are adversely affected when the amount of silica is increased or when magnesia is added in the form of fines. These findings suggest that medium and fine magnesia particles and an optimum amount of silica in the matrix composition of a spinel forming castable are necessary to obtain a matrix with increased alumina rich spinel content with controlled permanent linear change and porosity when exposed to high temperature during service.
{"title":"Influence of silica and magnesia on in situ spinel formation in alumina–magnesia castable","authors":"P. Nandi, A. Garg, R. Singh, B. Chattoraj","doi":"10.1179/096797804225012864","DOIUrl":"https://doi.org/10.1179/096797804225012864","url":null,"abstract":"Abstract The present study was carried out on the matrix composition of spinel forming high alumina castable to determine the effects of silica, magnesia particle size and temperature on spinel formation, the alumina content of the spinel formed, and associated physical characteristics at high temperature. It was found that an increase in silica content and use of finer magnesia helps to increase spinel formation. However to increase the alumina content of the spinel, increased temperature and magnesia particle size were more effective than an increased amount of silica. Furthermore the permanent linear change and porosity of the matrix are adversely affected when the amount of silica is increased or when magnesia is added in the form of fines. These findings suggest that medium and fine magnesia particles and an optimum amount of silica in the matrix composition of a spinel forming castable are necessary to obtain a matrix with increased alumina rich spinel content with controlled permanent linear change and porosity when exposed to high temperature during service.","PeriodicalId":350675,"journal":{"name":"British Ceramic Transactions","volume":"13 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131540126","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2004-06-01DOI: 10.1179/096797804225012837
S. Lee, G. Rixecker, F. Aldinger, Sung-Churl Choi, K. Auh
Abstract The microstructures of silicate layers on Si3N4 ceramics formed by oxidation or by spray coating with SiO2 and subsequent annealing were compared in order to clarify the effects of oxidation on pore formation and crystallisation in the different surface layers. In samples containing Al2O3/Y2O3, intensive separation and dissolution of sialon grains from the bulk into the oxidised layer was observed, and this is likely to be one of the reasons for the lower oxidation resistance of Si3N4 sintered with Y2O3/Al2O3 than with MgO/Y2O3. Oxygen supplied from the atmosphere plays an important role in bubble formation and in the crystallisation of cristobalite in the silicate layer. The silicate coating layer inhibits the oxidation of Si3N4 effectively up to 1200°C. At 1300°C, uncoated samples gained 0·75 by weight after oxidation for 500 min, whereas the weight gain of spray coated Si3N4 was 0·4% under the same conditions.
{"title":"Microstructure and oxidation behaviour of silicate coating on Si3N4: comparison with native oxide layers","authors":"S. Lee, G. Rixecker, F. Aldinger, Sung-Churl Choi, K. Auh","doi":"10.1179/096797804225012837","DOIUrl":"https://doi.org/10.1179/096797804225012837","url":null,"abstract":"Abstract The microstructures of silicate layers on Si3N4 ceramics formed by oxidation or by spray coating with SiO2 and subsequent annealing were compared in order to clarify the effects of oxidation on pore formation and crystallisation in the different surface layers. In samples containing Al2O3/Y2O3, intensive separation and dissolution of sialon grains from the bulk into the oxidised layer was observed, and this is likely to be one of the reasons for the lower oxidation resistance of Si3N4 sintered with Y2O3/Al2O3 than with MgO/Y2O3. Oxygen supplied from the atmosphere plays an important role in bubble formation and in the crystallisation of cristobalite in the silicate layer. The silicate coating layer inhibits the oxidation of Si3N4 effectively up to 1200°C. At 1300°C, uncoated samples gained 0·75 by weight after oxidation for 500 min, whereas the weight gain of spray coated Si3N4 was 0·4% under the same conditions.","PeriodicalId":350675,"journal":{"name":"British Ceramic Transactions","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126331689","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2004-04-01DOI: 10.1179/096797804225012747
S. Wada, T. Tsurumi
Abstract Engineered domain configurations with different domain sizes were induced in [111]c oriented tetragonal barium titanate BaTiO3 single crystals, and their piezoelectric properties investigated as a function of domain size. Prior to this study, the dependence of domain configuration on temperature and electric field E was investigated using polarised light microscopy to establish the optimum conditions for domain size control. As a result, above the Curie temperature Tc of 132.2°C, when E greater than 6 kV cm−1 was applied along the [111]c direction, an engineered domain configuration with fine domain structure appeared. Moreover, it was also found that this fine domain structure was still stable at room temperature in the absence of electric field. Finally, the piezoelectric properties were measured using 31 resonators with three domain sizes, and it was found that piezoelectric properties such as d31 and k31 increased significantly with decreasing domain size.
{"title":"Enhanced piezoelectricity of barium titanate single crystals with engineered domain configuration","authors":"S. Wada, T. Tsurumi","doi":"10.1179/096797804225012747","DOIUrl":"https://doi.org/10.1179/096797804225012747","url":null,"abstract":"Abstract Engineered domain configurations with different domain sizes were induced in [111]c oriented tetragonal barium titanate BaTiO3 single crystals, and their piezoelectric properties investigated as a function of domain size. Prior to this study, the dependence of domain configuration on temperature and electric field E was investigated using polarised light microscopy to establish the optimum conditions for domain size control. As a result, above the Curie temperature Tc of 132.2°C, when E greater than 6 kV cm−1 was applied along the [111]c direction, an engineered domain configuration with fine domain structure appeared. Moreover, it was also found that this fine domain structure was still stable at room temperature in the absence of electric field. Finally, the piezoelectric properties were measured using 31 resonators with three domain sizes, and it was found that piezoelectric properties such as d31 and k31 increased significantly with decreasing domain size.","PeriodicalId":350675,"journal":{"name":"British Ceramic Transactions","volume":"84 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124846302","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2004-04-01DOI: 10.1179/096797804225012774
W. Cao
Abstract Phenomenological theories for ferroelectrics are based on Landau–Devonshire type models, which can be constructed based on thermodynamic principles and symmetry relationships between parent and product phases. Phenomenological theories can be directly linked to measurable macroscopic quantities and at the same time preserve microscopic information. The competition between gradient energy and non-linear energy in Ginzburg–Landau type models provides an interpretation of inhomogeneous structures in ferroelectrics, for example twins and domain walls. Phenomenological models can be extended to antiferroelectric systems using a multicomponent order parameter related to microscopic local dipoles, rather than the average polarisation vector. Such a model can provide a more rigorous description of the antiferroelectric phase transition.
{"title":"Phenomenological theories of ferroelectric phase transitions","authors":"W. Cao","doi":"10.1179/096797804225012774","DOIUrl":"https://doi.org/10.1179/096797804225012774","url":null,"abstract":"Abstract Phenomenological theories for ferroelectrics are based on Landau–Devonshire type models, which can be constructed based on thermodynamic principles and symmetry relationships between parent and product phases. Phenomenological theories can be directly linked to measurable macroscopic quantities and at the same time preserve microscopic information. The competition between gradient energy and non-linear energy in Ginzburg–Landau type models provides an interpretation of inhomogeneous structures in ferroelectrics, for example twins and domain walls. Phenomenological models can be extended to antiferroelectric systems using a multicomponent order parameter related to microscopic local dipoles, rather than the average polarisation vector. Such a model can provide a more rigorous description of the antiferroelectric phase transition.","PeriodicalId":350675,"journal":{"name":"British Ceramic Transactions","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129782178","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2004-04-01DOI: 10.1179/096797804225012800
J. Fousek
Abstract Eric Cross has been one of the principal contributors to the solid state science literature over the last 40 years. In ferroic materials in particular his publications count as probably the single most cited body of work of any researcher in the field. This paper reviews some of his most fundamental contributions, concentrating in the main on older and by now 'classic' research, from studies of bismuth titanate, improper ferroelectrics and relaxors, through discovery of new properties such as ferroelastoelectricity and the flexoelectric effect, to work directed towards applications. The closing section discusses domain engineering.
{"title":"Selected research areas initiated by Leslie Eric Cross","authors":"J. Fousek","doi":"10.1179/096797804225012800","DOIUrl":"https://doi.org/10.1179/096797804225012800","url":null,"abstract":"Abstract Eric Cross has been one of the principal contributors to the solid state science literature over the last 40 years. In ferroic materials in particular his publications count as probably the single most cited body of work of any researcher in the field. This paper reviews some of his most fundamental contributions, concentrating in the main on older and by now 'classic' research, from studies of bismuth titanate, improper ferroelectrics and relaxors, through discovery of new properties such as ferroelastoelectricity and the flexoelectric effect, to work directed towards applications. The closing section discusses domain engineering.","PeriodicalId":350675,"journal":{"name":"British Ceramic Transactions","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122939783","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2004-04-01DOI: 10.1179/096797804225012756
R. J. Ong, D. Payne
Abstract The chemical method of solution deposition of Pb(Zr0·53Ti0·47)O3(PZT 53/47) thin layers on silicon involves shrinkage and stress development with heat treatment. Results are reported for shrinkage, as determined by in situ ellipsometry, and stress, measured by in situ laser reflectance, up to a maximum temperature of 700°C. Densification, thermal analysis, pyrolysis and crystallisation data are given and related to stress development as a function of sequential buildup of additional layers. For example, a residual tensile stress of around + 125 MPa was measured at room temperature for the first layer (inferred to be amorphous by the lack of XRD response). The stress magnitude decreased with increasing number of layers deposited. Observations are reported for the crystallisation of a fluorite phase on Si, and the formation of a lead silicate interfacial layer.
{"title":"Chemical solution deposition of PZT thin layers on silicon: densification and stress development","authors":"R. J. Ong, D. Payne","doi":"10.1179/096797804225012756","DOIUrl":"https://doi.org/10.1179/096797804225012756","url":null,"abstract":"Abstract The chemical method of solution deposition of Pb(Zr0·53Ti0·47)O3(PZT 53/47) thin layers on silicon involves shrinkage and stress development with heat treatment. Results are reported for shrinkage, as determined by in situ ellipsometry, and stress, measured by in situ laser reflectance, up to a maximum temperature of 700°C. Densification, thermal analysis, pyrolysis and crystallisation data are given and related to stress development as a function of sequential buildup of additional layers. For example, a residual tensile stress of around + 125 MPa was measured at room temperature for the first layer (inferred to be amorphous by the lack of XRD response). The stress magnitude decreased with increasing number of layers deposited. Observations are reported for the crystallisation of a fluorite phase on Si, and the formation of a lead silicate interfacial layer.","PeriodicalId":350675,"journal":{"name":"British Ceramic Transactions","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125855910","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2004-04-01DOI: 10.1179/096797804225012765
S. Lang
Abstract Pyroelectricity was probably first observed by the Greeks more than 24 centuries ago. The philosopher Theophrastus wrote that lyngourion (most likely the mineral tourmaline) had the property of attracting straws and bits of wood. For two millennia the peculiar properties of tourmaline were more a part of mythology than of science. In the eighteenth century pyroelectric studies made a major contribution to the development of our understanding of electrostatics. In the nineteenth, research on pyroelectricity added to our knowledge of mineralogy, thermodynamics and crystal physics. Pyroelectricity gave birth to piezoelectricity in 1880, and to ferroelectricity in 1920. The field of pyroelectricity flourished in the twentieth century with many applications, particularly in inf rared detection and thermal imaging. Pyroelectric sensors have been carried on many space missions and have contributed significantly to our astronomical knowledge.
{"title":"A 2400 year history of pyroelectricity: from Ancient Greece to exploration of the solar system","authors":"S. Lang","doi":"10.1179/096797804225012765","DOIUrl":"https://doi.org/10.1179/096797804225012765","url":null,"abstract":"Abstract Pyroelectricity was probably first observed by the Greeks more than 24 centuries ago. The philosopher Theophrastus wrote that lyngourion (most likely the mineral tourmaline) had the property of attracting straws and bits of wood. For two millennia the peculiar properties of tourmaline were more a part of mythology than of science. In the eighteenth century pyroelectric studies made a major contribution to the development of our understanding of electrostatics. In the nineteenth, research on pyroelectricity added to our knowledge of mineralogy, thermodynamics and crystal physics. Pyroelectricity gave birth to piezoelectricity in 1880, and to ferroelectricity in 1920. The field of pyroelectricity flourished in the twentieth century with many applications, particularly in inf rared detection and thermal imaging. Pyroelectric sensors have been carried on many space missions and have contributed significantly to our astronomical knowledge.","PeriodicalId":350675,"journal":{"name":"British Ceramic Transactions","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125243918","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2004-04-01DOI: 10.1179/096797804225012783
G. Rossetti
Abstract Alloys of PbZrO3–PbT iO3 (PZT) exhibit a complex series of ferroic lattice instabilities that depend on the Zr/Ti ratio and give rise to exceptional pyroelectric and piezoelectric properties. An approach based on energetics and crystal chemical systematics is discussed that relates structure and bonding in PZT to its subsolidus phase diagram. Heats of formation, heat contents and contributions to lattice energies across the phase diagram are correlated with the perovskite tolerance factor and with displacements of Pb and (Zr, Ti) cations f rom their high symmetry positions. It is shown that at 973 K the cubic phase contains precursors of the lattice instabilities and the differing displacements of Ti and Zr inferred for the lower symmetry phases at lower temperatures. Modulations in local structure, revealed in the ratio of Pb to (Zr, Ti) cation displacements, are related to the transition temperature from the paraelectric cubic phase to the ferroic phases.
{"title":"Structure and bonding in PbZrO3–PbTiO3 (PZT) alloys","authors":"G. Rossetti","doi":"10.1179/096797804225012783","DOIUrl":"https://doi.org/10.1179/096797804225012783","url":null,"abstract":"Abstract Alloys of PbZrO3–PbT iO3 (PZT) exhibit a complex series of ferroic lattice instabilities that depend on the Zr/Ti ratio and give rise to exceptional pyroelectric and piezoelectric properties. An approach based on energetics and crystal chemical systematics is discussed that relates structure and bonding in PZT to its subsolidus phase diagram. Heats of formation, heat contents and contributions to lattice energies across the phase diagram are correlated with the perovskite tolerance factor and with displacements of Pb and (Zr, Ti) cations f rom their high symmetry positions. It is shown that at 973 K the cubic phase contains precursors of the lattice instabilities and the differing displacements of Ti and Zr inferred for the lower symmetry phases at lower temperatures. Modulations in local structure, revealed in the ratio of Pb to (Zr, Ti) cation displacements, are related to the transition temperature from the paraelectric cubic phase to the ferroic phases.","PeriodicalId":350675,"journal":{"name":"British Ceramic Transactions","volume":"103 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128851898","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2004-04-01DOI: 10.1179/096797804225012792
M. Glinchuk
Abstract A brief review is presented of recent results derived from the random field theory approach to describing relaxor ferroelectric properties. The key point in this approach is that the random field originating f rom chemical disorder of relaxor ferroelectrics destroys long range polar order, which could otherwise exist at temperatures below the Burns temperature Td. As a result, polar clusters appear of size Rc (the correlation radius of Burns reference phase), corresponding to the Cross superparaelectric phase. The relaxor properties can be calculated by averaging the electric field dependence of the paraelectric Burns reference phase with the random field distribution function of a suitable property. The distribution functions for the cases of linear and non-linear random field contributions are calculated using the statistical physics framework for electric dipoles, point charges and dilatational centres as random field sources. These calculations allow explanation of the observed Vogel–Fulcher law and non-Debye character of the dynamic dielectric response; of stiff and soft response to dc field of non-linear susceptibility; of unusual Rc temperature dependence; as well as of dielectric response anomalies in 1:1 family relaxors. The correlation radius and relaxation time distribution functions are calculated using the random field distribution function. Calculated phase diagrams for mixed relaxors, allowing for non-linear and spatial correlation effects, give a good fit to the experimental results. Comparison of calculated and observed properties leads to the conclusion that a mixed ferroglass phase with coexisting short and long polar order is the most probable state for all relaxors, the degree of mixing being the essential factor for a relaxor.
{"title":"Relaxor ferroelectrics: from Cross superparaelectric model to random field theory","authors":"M. Glinchuk","doi":"10.1179/096797804225012792","DOIUrl":"https://doi.org/10.1179/096797804225012792","url":null,"abstract":"Abstract A brief review is presented of recent results derived from the random field theory approach to describing relaxor ferroelectric properties. The key point in this approach is that the random field originating f rom chemical disorder of relaxor ferroelectrics destroys long range polar order, which could otherwise exist at temperatures below the Burns temperature Td. As a result, polar clusters appear of size Rc (the correlation radius of Burns reference phase), corresponding to the Cross superparaelectric phase. The relaxor properties can be calculated by averaging the electric field dependence of the paraelectric Burns reference phase with the random field distribution function of a suitable property. The distribution functions for the cases of linear and non-linear random field contributions are calculated using the statistical physics framework for electric dipoles, point charges and dilatational centres as random field sources. These calculations allow explanation of the observed Vogel–Fulcher law and non-Debye character of the dynamic dielectric response; of stiff and soft response to dc field of non-linear susceptibility; of unusual Rc temperature dependence; as well as of dielectric response anomalies in 1:1 family relaxors. The correlation radius and relaxation time distribution functions are calculated using the random field distribution function. Calculated phase diagrams for mixed relaxors, allowing for non-linear and spatial correlation effects, give a good fit to the experimental results. Comparison of calculated and observed properties leads to the conclusion that a mixed ferroglass phase with coexisting short and long polar order is the most probable state for all relaxors, the degree of mixing being the essential factor for a relaxor.","PeriodicalId":350675,"journal":{"name":"British Ceramic Transactions","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127598644","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2004-04-01DOI: 10.1179/096797804225012855
A. Amin, L. Cross
Abstract Optical and dielectric studies of oriented and poled single crystal compositions on both sides of the morphotropic phase boundary in (1− x)Pb(Zn1/3Nb2/3)O3–xPbT iO3 have revealed an intermediate, metastable, ferroelectric orthorhombic state (FO) in a narrow composition range between the ferroelectric rhombohedral (FR) and tetragonal (FT) phases, which has also been identified from pyroelectric and dielectric data. Recently published structural data confirm this orthorhombic state for 0·08 < x < 0·11. Similarly, dielectric studies and electromechanical measurements on rhombohedral Pb(Mg1/3Nb2/3)O3–PbT iO3 single crystals have revealed an intermediate, metastable FO state at high temperature. Structural evidence of the orthorhombic phase in this system has also recently been reported. In the present paper it is shown that a metastable orthorhombic state is always close to but unstable with respect to the FR–FT degenerate states (morphotropy), as predicted by a phenomenological model for A(BI1− xBIIx)O3 ferroelectrics. Conditions for stabilising the nearly degenerate FR, FT and FO states in the Pb(BI1/3BII2/3)O3–PbT iO3 single crystal system are discussed in terms of the energy function tensor coefficients.
{"title":"Intermediate states in Pb(BI1/3II2/3)O3–PbTiO3 ferroelectric single crystals","authors":"A. Amin, L. Cross","doi":"10.1179/096797804225012855","DOIUrl":"https://doi.org/10.1179/096797804225012855","url":null,"abstract":"Abstract Optical and dielectric studies of oriented and poled single crystal compositions on both sides of the morphotropic phase boundary in (1− x)Pb(Zn1/3Nb2/3)O3–xPbT iO3 have revealed an intermediate, metastable, ferroelectric orthorhombic state (FO) in a narrow composition range between the ferroelectric rhombohedral (FR) and tetragonal (FT) phases, which has also been identified from pyroelectric and dielectric data. Recently published structural data confirm this orthorhombic state for 0·08 < x < 0·11. Similarly, dielectric studies and electromechanical measurements on rhombohedral Pb(Mg1/3Nb2/3)O3–PbT iO3 single crystals have revealed an intermediate, metastable FO state at high temperature. Structural evidence of the orthorhombic phase in this system has also recently been reported. In the present paper it is shown that a metastable orthorhombic state is always close to but unstable with respect to the FR–FT degenerate states (morphotropy), as predicted by a phenomenological model for A(BI1− xBIIx)O3 ferroelectrics. Conditions for stabilising the nearly degenerate FR, FT and FO states in the Pb(BI1/3BII2/3)O3–PbT iO3 single crystal system are discussed in terms of the energy function tensor coefficients.","PeriodicalId":350675,"journal":{"name":"British Ceramic Transactions","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127042687","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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