Pub Date : 2008-12-02DOI: 10.1109/ISAF.2008.4693924
Huadong Li, G. Subramanyam, Jiadong Wang
Thin film Ferroelectric capacitance can be obtained with two methods. Capacitance obtained by the derivative of its hysteresis loop is related to large applied signal. Capacitance measured directly with small applied alternate current signal together with slow changing dc bias is related to small signal circuit analysis. This paper investigated the relationship between the two types of capacitance. Measurements show that C-V curves obtained with the first method have much sharper peaks and higher peak values. A model, which divides the polarization of Pb (Zr, Ti) O3 (PZT) into linear polarization and switching polarization, was utilized to analyze the mechanism.
{"title":"Capacitance of thin Ferroelectric films obtained with different methods","authors":"Huadong Li, G. Subramanyam, Jiadong Wang","doi":"10.1109/ISAF.2008.4693924","DOIUrl":"https://doi.org/10.1109/ISAF.2008.4693924","url":null,"abstract":"Thin film Ferroelectric capacitance can be obtained with two methods. Capacitance obtained by the derivative of its hysteresis loop is related to large applied signal. Capacitance measured directly with small applied alternate current signal together with slow changing dc bias is related to small signal circuit analysis. This paper investigated the relationship between the two types of capacitance. Measurements show that C-V curves obtained with the first method have much sharper peaks and higher peak values. A model, which divides the polarization of Pb (Zr, Ti) O3 (PZT) into linear polarization and switching polarization, was utilized to analyze the mechanism.","PeriodicalId":228914,"journal":{"name":"2008 17th IEEE International Symposium on the Applications of Ferroelectrics","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124002495","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 : 2008-12-02DOI: 10.1109/ISAF.2008.4693811
K. Kerman, M. Abazari, N. Marandian-Hagh, E. K. Akdoğan, A. Safari
Recent advances in (K,Na)NbO3-based ferroelectrics is reviewed, with special emphasis on the (K,Na)NbO3-LiTaO3-LiSbO3 system. Processing issues are elaborated on. The importance of precursor purity, moisture sensitivity and oxygen content on the dielectric and piezoelectric properties will be shown. Properties of prototype transducers are given and it will be shown that high performance metrics reminiscent to PZT-4 based transducers can be reached. Origins of high piezoelectric activity in the (K0.5Na0.5Li0.04)(Nb0.86Ta0.04Sb0.06)O3 is discussed, where it will be shown that this particular composition has a polymorphic phase transition in the vicinity of room temperature, and does not exhibit a morphotropic phase boundary..
{"title":"Lead free (K,Na)NbO3-based piezoelectric ceramics and transducers","authors":"K. Kerman, M. Abazari, N. Marandian-Hagh, E. K. Akdoğan, A. Safari","doi":"10.1109/ISAF.2008.4693811","DOIUrl":"https://doi.org/10.1109/ISAF.2008.4693811","url":null,"abstract":"Recent advances in (K,Na)NbO3-based ferroelectrics is reviewed, with special emphasis on the (K,Na)NbO3-LiTaO3-LiSbO3 system. Processing issues are elaborated on. The importance of precursor purity, moisture sensitivity and oxygen content on the dielectric and piezoelectric properties will be shown. Properties of prototype transducers are given and it will be shown that high performance metrics reminiscent to PZT-4 based transducers can be reached. Origins of high piezoelectric activity in the (K0.5Na0.5Li0.04)(Nb0.86Ta0.04Sb0.06)O3 is discussed, where it will be shown that this particular composition has a polymorphic phase transition in the vicinity of room temperature, and does not exhibit a morphotropic phase boundary..","PeriodicalId":228914,"journal":{"name":"2008 17th IEEE International Symposium on the Applications of Ferroelectrics","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115298624","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 : 2008-12-02DOI: 10.1109/ISAF.2008.4693740
Badri Rangarajan, T. Shrout, M. Lanagan
The possible use of glass ceramics as high energy density capacitors in heart defibrillators and hybrid automotive vehicles is explored. Glass ceramics, lead sodium niobate silicate (PNNS), barium sodium niobate silicate (BNNS) and barium titanate silicate (BTS), allow the development of dielectrics with various permittivity values ranging from 20 to 700. Glasses were formed by melt-rolling the respective constituents which were then crystallized by reheating the glass at higher temperatures. Heat treatment schedules were formulated based on DTA results. A spectrum of crystalline phases, ranging from perovskites, tungsten bronzes and pyrochlores to fresnoites, were generated within the various glass matrices. Disadvantages, such as difficult glass formability, less control over crystallization due to multiphase formation etc., associated with high permittivity PNNS and BNNS glass ceramics served as the motivating factor for exploring low permittivity glass ceramics. BTS glass ceramics exhibit excellent stability in permittivity, high resistivity and low loss over the measured range of temperature. Thin samples with pristine surfaces are required for achieving high breakdown strength values. Investigation of the crystallization kinetics of BTS glass would provide further insight into exploring glass nano-composites, analogous to polymer nano-composites.
{"title":"Glass ceramic dielectrics: Energy storage and breakdown","authors":"Badri Rangarajan, T. Shrout, M. Lanagan","doi":"10.1109/ISAF.2008.4693740","DOIUrl":"https://doi.org/10.1109/ISAF.2008.4693740","url":null,"abstract":"The possible use of glass ceramics as high energy density capacitors in heart defibrillators and hybrid automotive vehicles is explored. Glass ceramics, lead sodium niobate silicate (PNNS), barium sodium niobate silicate (BNNS) and barium titanate silicate (BTS), allow the development of dielectrics with various permittivity values ranging from 20 to 700. Glasses were formed by melt-rolling the respective constituents which were then crystallized by reheating the glass at higher temperatures. Heat treatment schedules were formulated based on DTA results. A spectrum of crystalline phases, ranging from perovskites, tungsten bronzes and pyrochlores to fresnoites, were generated within the various glass matrices. Disadvantages, such as difficult glass formability, less control over crystallization due to multiphase formation etc., associated with high permittivity PNNS and BNNS glass ceramics served as the motivating factor for exploring low permittivity glass ceramics. BTS glass ceramics exhibit excellent stability in permittivity, high resistivity and low loss over the measured range of temperature. Thin samples with pristine surfaces are required for achieving high breakdown strength values. Investigation of the crystallization kinetics of BTS glass would provide further insight into exploring glass nano-composites, analogous to polymer nano-composites.","PeriodicalId":228914,"journal":{"name":"2008 17th IEEE International Symposium on the Applications of Ferroelectrics","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114761564","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 : 2008-12-02DOI: 10.1109/ISAF.2008.4693915
J. Son, J. Cagnon, N. H. Finstrom, D. Boesch, J. Lu, S. Stemmer
We report on some of the key properties of ferroelectric and high-permittivity thin films relevant for their application in metal/insulator/metal structures, such as voltage tunable capacitors and novel memories. We use a model system, Pt/SrTiO3/Pt thin film structures, with microstructures, stress states and point defects characterized by advanced transmission electron microscopy techniques, high-resolution x-ray diffraction and wafer curvature measurements. We investigate the relation between defects and dielectric properties, measured at frequencies up to 1 GHz. We discuss the origins of dielectric losses in these films and the role of point defects, such as oxygen vacancies. We report on dielectric deadlayers, which cause a significant reduction in the dielectric tunabilities. We discuss the influence of dielectric relaxation on the thermal leakage characteristics of textured and epitaxial Pt/SrTiO3/Pt thin film structures. We also discuss the properties of Pt/SrTiO3/Pt structures with ultrathin (5 ¿ 10 nm) SrTiO3 films.
{"title":"Relationship between defects and the dielectric and transport properties of SrTiO3 thin films","authors":"J. Son, J. Cagnon, N. H. Finstrom, D. Boesch, J. Lu, S. Stemmer","doi":"10.1109/ISAF.2008.4693915","DOIUrl":"https://doi.org/10.1109/ISAF.2008.4693915","url":null,"abstract":"We report on some of the key properties of ferroelectric and high-permittivity thin films relevant for their application in metal/insulator/metal structures, such as voltage tunable capacitors and novel memories. We use a model system, Pt/SrTiO3/Pt thin film structures, with microstructures, stress states and point defects characterized by advanced transmission electron microscopy techniques, high-resolution x-ray diffraction and wafer curvature measurements. We investigate the relation between defects and dielectric properties, measured at frequencies up to 1 GHz. We discuss the origins of dielectric losses in these films and the role of point defects, such as oxygen vacancies. We report on dielectric deadlayers, which cause a significant reduction in the dielectric tunabilities. We discuss the influence of dielectric relaxation on the thermal leakage characteristics of textured and epitaxial Pt/SrTiO3/Pt thin film structures. We also discuss the properties of Pt/SrTiO3/Pt structures with ultrathin (5 ¿ 10 nm) SrTiO3 films.","PeriodicalId":228914,"journal":{"name":"2008 17th IEEE International Symposium on the Applications of Ferroelectrics","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127235845","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 : 2008-12-02DOI: 10.1109/ISAF.2008.4693846
M. Losego, H. S. Craft, S. Mita, T. Rice, R. Collazo, Z. Sitar, J. Maria
Integration of functional complex oxides with gallium nitride is attractive for advanced device architectures including smart FETs and high-temperature electronics. Inclusion of large bandgap interfacial oxide layers are of interest for band line-up compatibility. This presentation reviews work on the epitaxial growth of large bandgap rocksalt oxide buffer layers including MgO and CaO by molecular beam epitaxy. It also discusses the epitaxial deposition of ferroelectric oxides by rf magnetron sputtering.
{"title":"TF004 - interfacing complex oxides to gallium nitride","authors":"M. Losego, H. S. Craft, S. Mita, T. Rice, R. Collazo, Z. Sitar, J. Maria","doi":"10.1109/ISAF.2008.4693846","DOIUrl":"https://doi.org/10.1109/ISAF.2008.4693846","url":null,"abstract":"Integration of functional complex oxides with gallium nitride is attractive for advanced device architectures including smart FETs and high-temperature electronics. Inclusion of large bandgap interfacial oxide layers are of interest for band line-up compatibility. This presentation reviews work on the epitaxial growth of large bandgap rocksalt oxide buffer layers including MgO and CaO by molecular beam epitaxy. It also discusses the epitaxial deposition of ferroelectric oxides by rf magnetron sputtering.","PeriodicalId":228914,"journal":{"name":"2008 17th IEEE International Symposium on the Applications of Ferroelectrics","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125335810","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 : 2008-12-02DOI: 10.1109/ISAF.2008.4693727
N. Kawazu, K. Kikuchi, D. Akai, K. Sawada, M. Ishida
Integrated 32 × 32 pyroelectric IR sensor array in nMOS/JFET circuitry using highly (001) oriented Pb(Zr0.4, Ti0.6)O3 (PZT) thin films on epitaxial y-Al2O3/Si substrates has been fabricated on the one chip. The sensor array utilizes a sol-gel deposited PZT(001) thin film as a pyroelectric material, an n-JFET as a low noise detection device, and a micromachined membrane supported by four beams as a thermal isolation structure on epitaxial Pt(001)/y-Al2O3(001)/Si(001) substrates.
{"title":"Integrated 32 × 32 pyroelectric ir sensor array in nmos/jfet circuitry using highly (001) oriented pzt thin films on epitaxial y-al2o3/si substrates","authors":"N. Kawazu, K. Kikuchi, D. Akai, K. Sawada, M. Ishida","doi":"10.1109/ISAF.2008.4693727","DOIUrl":"https://doi.org/10.1109/ISAF.2008.4693727","url":null,"abstract":"Integrated 32 × 32 pyroelectric IR sensor array in nMOS/JFET circuitry using highly (001) oriented Pb(Zr0.4, Ti0.6)O3 (PZT) thin films on epitaxial y-Al2O3/Si substrates has been fabricated on the one chip. The sensor array utilizes a sol-gel deposited PZT(001) thin film as a pyroelectric material, an n-JFET as a low noise detection device, and a micromachined membrane supported by four beams as a thermal isolation structure on epitaxial Pt(001)/y-Al2O3(001)/Si(001) substrates.","PeriodicalId":228914,"journal":{"name":"2008 17th IEEE International Symposium on the Applications of Ferroelectrics","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121003169","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 : 2008-12-02DOI: 10.1109/ISAF.2008.4693868
N. Karan, D. Pradhan, J. Saavedra-Arias, N. M. Murari, R. Thomas, R. Katiyar, K. Sudheendran, K. Raju
(Pb1¿xSrx)(Zr0.5Ti0.5)O3 ( x= 0 to 0.65) thin films were grown on Pt/TiO2/SiO2/Si substrates by chemical solution deposition. Films were crystallized in the single phase perovskite structure in the temperature range ( 550¿700°C). Dielectric constant and loss tangent at room temperature reduced as the percentage of Sr substitution increased at the A-site of this perovskite structure. The phase transition temperature (Tc) lowered with Sr-substitution and Tc below the room temperature was obtained for composition with Sr ¿ 40%. The room temperature tunability reduced with Sr substitution, however, the k-factor slightly improved.
{"title":"Effect of Sr substitution on tunability and dielectric properties in Pb(Zr0.50Ti0.50)O3 thin films fabricated by chemical solution deposition","authors":"N. Karan, D. Pradhan, J. Saavedra-Arias, N. M. Murari, R. Thomas, R. Katiyar, K. Sudheendran, K. Raju","doi":"10.1109/ISAF.2008.4693868","DOIUrl":"https://doi.org/10.1109/ISAF.2008.4693868","url":null,"abstract":"(Pb1¿xSrx)(Zr0.5Ti0.5)O3 ( x= 0 to 0.65) thin films were grown on Pt/TiO2/SiO2/Si substrates by chemical solution deposition. Films were crystallized in the single phase perovskite structure in the temperature range ( 550¿700°C). Dielectric constant and loss tangent at room temperature reduced as the percentage of Sr substitution increased at the A-site of this perovskite structure. The phase transition temperature (Tc) lowered with Sr-substitution and Tc below the room temperature was obtained for composition with Sr ¿ 40%. The room temperature tunability reduced with Sr substitution, however, the k-factor slightly improved.","PeriodicalId":228914,"journal":{"name":"2008 17th IEEE International Symposium on the Applications of Ferroelectrics","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126708412","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 : 2008-12-02DOI: 10.1109/ISAF.2008.4693808
A. Rybianets, Anastasia Rybianets
A new method of PZT/PZT ceramic piezocomposites fabrication is proposed. Samples of piezocomposites with the volume fraction of components 0¿100% for different PZT compositions were fabricated and measured. A line of chemically, thermally, and technologically compatible PZT matrix and filling compositions were chosen. Different types of PZT type piezoceramics powders and pre-sintered piezoceramic granules were used as matrix and filling components respectively. The size and shape of the filling particles were chosen as a compromise between maximal scattering and minimal interfacial area to minimize chemical interaction between two composite phases. Special pressing and firing regimes were used for formation of microporous piezoceramic matrix. Sintering of the composites was carried out at special thermal profiles preventing cracking because of shrinkage and thermal expansion of composite components. Complex sets of elastic, dielectric, and piezoelectric parameters of piezocomposites were determined by ultrasonic and impedance spectroscopy method using piezoelectric resonance analysis (PRAP) software. Microstructure of polished, chemically etched, and chipped surfaces of piezocomposite samples was observed with optical and scanning electron microscopes. New PZT/PZT ceramic piezocomposites are characterized by a unique spectrum of the electrophysical properties unachievable for standard PZT ceramic compositions and fabrication methods and can be useful for wide-band ultrasonic transducer applications.
{"title":"Dielectric, piezoelectric and elastic properties of PZT/PZT ceramic piezocomposites","authors":"A. Rybianets, Anastasia Rybianets","doi":"10.1109/ISAF.2008.4693808","DOIUrl":"https://doi.org/10.1109/ISAF.2008.4693808","url":null,"abstract":"A new method of PZT/PZT ceramic piezocomposites fabrication is proposed. Samples of piezocomposites with the volume fraction of components 0¿100% for different PZT compositions were fabricated and measured. A line of chemically, thermally, and technologically compatible PZT matrix and filling compositions were chosen. Different types of PZT type piezoceramics powders and pre-sintered piezoceramic granules were used as matrix and filling components respectively. The size and shape of the filling particles were chosen as a compromise between maximal scattering and minimal interfacial area to minimize chemical interaction between two composite phases. Special pressing and firing regimes were used for formation of microporous piezoceramic matrix. Sintering of the composites was carried out at special thermal profiles preventing cracking because of shrinkage and thermal expansion of composite components. Complex sets of elastic, dielectric, and piezoelectric parameters of piezocomposites were determined by ultrasonic and impedance spectroscopy method using piezoelectric resonance analysis (PRAP) software. Microstructure of polished, chemically etched, and chipped surfaces of piezocomposite samples was observed with optical and scanning electron microscopes. New PZT/PZT ceramic piezocomposites are characterized by a unique spectrum of the electrophysical properties unachievable for standard PZT ceramic compositions and fabrication methods and can be useful for wide-band ultrasonic transducer applications.","PeriodicalId":228914,"journal":{"name":"2008 17th IEEE International Symposium on the Applications of Ferroelectrics","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126402310","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 : 2008-12-02DOI: 10.1109/ISAF.2008.4693770
E. K. Akdoğan, A. Safari
The nonlinear dielectric properties of 0.9Pb[Mg1/3,Nb2/3]O3·0.1PbTiO3 (PMN-PT) and Ba[Ti0.85,Sn0.15]O3 (BTS) paraelectrics were studied experimentally and theoretically. The nonlinear dielectric response was measured in the parallel plate capacitor configuration, whereby the low frequency linear permittivity ( ¿33 ), and the higher order permittivities ( ¿3333, ¿333333 ) at 298 K were obtained as å33PMN-PT = 2.1x10¿7 and ¿33BTS = 4.1x10¿8 (F/m), ¿3333PMN-PT= ¿4.9x10¿20 and ¿333333BTS = 9.85x10¿34 (F3m/C2), and ¿333333PMT-PT = 7.6x10¿33 and ¿3333BTS = ¿7.3x10¿21 (F5m3/C4). By using a self-consistent thermodynamic theory in conjunction with the experimental data, we compute the E3 dependence of electrostatic energy ¿G , the field-induced polarization response P3 , the thermodynamic tunability ¿2P3/¿E32 , and prove that electrostatic free energy has to be expanded at least up to the sixth order in electric field define the critical field |E3*| at which maximum tunability is attained. We also show that |E3*| is a function on |¿3333|/¿333333 only. Consequently, we find |E3*|PMT-PT = 8.6x105 V/m and |E3*|BTS =8.0x105 V/m. We compute the engineering tunabilities as ¿PMN-PT =65% and ¿BTS =55%, and then define a normalized tunability ¿ to take into account the |E3*| parameter. Thereof, we determine |¿|PMT-PT = 8.1x10¿5 and |¿|BTS =6.4x10¿5 %/Vm¿1. Our results reveal that |E3*|BTS >|E3*|PMNPT although ¿BTS < ¿PMNPT, unequivocally showing the need for defining a critical field parameter in evaluating the nonlinear dielectric response and tunability in particular, and in nonlinear dielectrics in general. The results also indicate that the nonlinear dielectric properties of PMN-PT are an order of magnitude higher than that of BTS, which we discuss in the context of structure-property relations of relaxors.
{"title":"Fourth and sixth order nonlinear permittivity and thermodynamics of tunability in 0.9Pb(Mg1/3,Nb2/3)O3·0.1PbTiO3 and Ba(Ti0.85,Sn0.05)O3 paraelectric ceramics","authors":"E. K. Akdoğan, A. Safari","doi":"10.1109/ISAF.2008.4693770","DOIUrl":"https://doi.org/10.1109/ISAF.2008.4693770","url":null,"abstract":"The nonlinear dielectric properties of 0.9Pb[Mg1/3,Nb2/3]O3·0.1PbTiO3 (PMN-PT) and Ba[Ti0.85,Sn0.15]O3 (BTS) paraelectrics were studied experimentally and theoretically. The nonlinear dielectric response was measured in the parallel plate capacitor configuration, whereby the low frequency linear permittivity ( ¿33 ), and the higher order permittivities ( ¿3333, ¿333333 ) at 298 K were obtained as å33PMN-PT = 2.1x10¿7 and ¿33BTS = 4.1x10¿8 (F/m), ¿3333PMN-PT= ¿4.9x10¿20 and ¿333333BTS = 9.85x10¿34 (F3m/C2), and ¿333333PMT-PT = 7.6x10¿33 and ¿3333BTS = ¿7.3x10¿21 (F5m3/C4). By using a self-consistent thermodynamic theory in conjunction with the experimental data, we compute the E3 dependence of electrostatic energy ¿G , the field-induced polarization response P3 , the thermodynamic tunability ¿2P3/¿E32 , and prove that electrostatic free energy has to be expanded at least up to the sixth order in electric field define the critical field |E3*| at which maximum tunability is attained. We also show that |E3*| is a function on |¿3333|/¿333333 only. Consequently, we find |E3*|PMT-PT = 8.6x105 V/m and |E3*|BTS =8.0x105 V/m. We compute the engineering tunabilities as ¿PMN-PT =65% and ¿BTS =55%, and then define a normalized tunability ¿ to take into account the |E3*| parameter. Thereof, we determine |¿|PMT-PT = 8.1x10¿5 and |¿|BTS =6.4x10¿5 %/Vm¿1. Our results reveal that |E3*|BTS >|E3*|PMNPT although ¿BTS < ¿PMNPT, unequivocally showing the need for defining a critical field parameter in evaluating the nonlinear dielectric response and tunability in particular, and in nonlinear dielectrics in general. The results also indicate that the nonlinear dielectric properties of PMN-PT are an order of magnitude higher than that of BTS, which we discuss in the context of structure-property relations of relaxors.","PeriodicalId":228914,"journal":{"name":"2008 17th IEEE International Symposium on the Applications of Ferroelectrics","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123693209","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 : 2008-12-02DOI: 10.1109/ISAF.2008.4693956
K. Musselman, J. MacManus‐Driscoll, D. Iza, L. Schmidt‐Mende
Metal oxide nanostructures have garnered a lot of attention for use in hybrid solar cells. We report on the synthesis of ultra-thin nanoporous anodic alumina templates on indium tin oxide (ITO)/glass substrates. These templates have been used to electrochemically deposit free-standing arrays of Cu2O (p-type) and ZnO (n-type) nanowires over device-suitable areas (cm2). The nanostructures provide a large surface area for photovoltaic charge separation, while maintaining direct pathways for charge transport.
{"title":"Oxide nanowire arrays for hybrid solar cells","authors":"K. Musselman, J. MacManus‐Driscoll, D. Iza, L. Schmidt‐Mende","doi":"10.1109/ISAF.2008.4693956","DOIUrl":"https://doi.org/10.1109/ISAF.2008.4693956","url":null,"abstract":"Metal oxide nanostructures have garnered a lot of attention for use in hybrid solar cells. We report on the synthesis of ultra-thin nanoporous anodic alumina templates on indium tin oxide (ITO)/glass substrates. These templates have been used to electrochemically deposit free-standing arrays of Cu2O (p-type) and ZnO (n-type) nanowires over device-suitable areas (cm2). The nanostructures provide a large surface area for photovoltaic charge separation, while maintaining direct pathways for charge transport.","PeriodicalId":228914,"journal":{"name":"2008 17th IEEE International Symposium on the Applications of Ferroelectrics","volume":"66 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121521735","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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