Pub Date : 2007-05-27DOI: 10.1109/ISAF.2007.4393240
X. Tan, W. Qu, H. He
High electric fields were delivered to specimens during imaging in the transmission electron microscopy (TEM) chamber to reveal details of electric field-induced phenomena in ferroelectric oxides. These include the grain boundary cavitation in a PZT ceramic, the domain wall fracture in a Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT) single crystal, the transformation of incommensurate modulations in Pb0.99Nb0.02[(Zr1-xSnx)1-yTiy]0.98O3 (PZST100x/100y/2) ceramics, and the growth of polar nanodomains in a Sc-modified PMN ceramic.
{"title":"In situ TEM Study of Electric Field-Induced Phenomena in Ferroelectric Ceramics","authors":"X. Tan, W. Qu, H. He","doi":"10.1109/ISAF.2007.4393240","DOIUrl":"https://doi.org/10.1109/ISAF.2007.4393240","url":null,"abstract":"High electric fields were delivered to specimens during imaging in the transmission electron microscopy (TEM) chamber to reveal details of electric field-induced phenomena in ferroelectric oxides. These include the grain boundary cavitation in a PZT ceramic, the domain wall fracture in a Pb(Mg<sub>1/3</sub>Nb<sub>2/3</sub>)O<sub>3</sub>-PbTiO<sub>3</sub> (PMN-PT) single crystal, the transformation of incommensurate modulations in Pb<sub>0.99</sub>Nb<sub>0.02</sub>[(Zr<sub>1-x</sub>Sn<sub>x</sub>)<sub>1-y</sub>Ti<sub>y</sub>]<sub>0.98</sub>O<sub>3</sub> (PZST100x/100y/2) ceramics, and the growth of polar nanodomains in a Sc-modified PMN ceramic.","PeriodicalId":321007,"journal":{"name":"2007 Sixteenth IEEE International Symposium on the Applications of Ferroelectrics","volume":"289 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134422066","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 : 2007-05-27DOI: 10.1109/ISAF.2007.4393225
T. Nishida, M. Echizen, T. Takeda, K. Uchiyama, T. Shiosaki
Pb(Zr, Ti)O3 (PZT) ferroelectric thin films have been extensively investigated because of their potential for FeRAM and MEMS device applications. However, realization of high performance devices has not been achieved due to degradation problems for the PZT films, such as fatigue and imprinting. The degradation is caused by crystal defects in the films, however, properties of the defects have not yet been sufficiently clarified. We have therefore attempted to investigate crystal defects in PZT films by thermally stimulated current (TSC) measurements. Current peaks due to the defects were detected in the measurements, and the origin of the observed defects was identified by systematic evaluation. It was revealed that the activation energy of the TSC peaks ranged from 0.75 eV to 0.95 eV, and the peaks were related to PbOx defects at the interface between the electrodes and the PZT layer.
{"title":"Investigation of Crystal Defects in Lead Zirconate Titanate Films by Thermally Stimulated Current Measurement","authors":"T. Nishida, M. Echizen, T. Takeda, K. Uchiyama, T. Shiosaki","doi":"10.1109/ISAF.2007.4393225","DOIUrl":"https://doi.org/10.1109/ISAF.2007.4393225","url":null,"abstract":"Pb(Zr, Ti)O3 (PZT) ferroelectric thin films have been extensively investigated because of their potential for FeRAM and MEMS device applications. However, realization of high performance devices has not been achieved due to degradation problems for the PZT films, such as fatigue and imprinting. The degradation is caused by crystal defects in the films, however, properties of the defects have not yet been sufficiently clarified. We have therefore attempted to investigate crystal defects in PZT films by thermally stimulated current (TSC) measurements. Current peaks due to the defects were detected in the measurements, and the origin of the observed defects was identified by systematic evaluation. It was revealed that the activation energy of the TSC peaks ranged from 0.75 eV to 0.95 eV, and the peaks were related to PbOx defects at the interface between the electrodes and the PZT layer.","PeriodicalId":321007,"journal":{"name":"2007 Sixteenth IEEE International Symposium on the Applications of Ferroelectrics","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132938031","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 : 2007-05-27DOI: 10.1109/ISAF.2007.4393235
E. Matsushita, S. Segawa
By extending the soft-phonon theory, a quantum paraelectric(PE)-ferroelectric(FE) transition in SrTi16O3 (ST016) is studied from the viewpoint of the important role of optical phonons in perovskite-oxides. In spite of intrinsic quantum fluctuation of large zero-point vibration induced from light O-atoms, the FE transition due to the O-isotope exchange 16O1-x18Ox is explained in a unified picture by combining with the applied pressure (or uniaxial stress) effect. The calculated Tc as the function of x is compared with the experimental data in rather good agreement, and the origin of quantum paraelectricity in STO 16 is discussed in comparison with pressure effect in hydrogen-bonded ferroelectrics KH2PO4 (KDP). As the result, it is suggested that quantum PE-FE transition with the critical exponent 1/2 at Tc=0 where the FE transition will start, must be analyzed by a microscopic theory exceeding soft phonon theory.
{"title":"Note on Oxygen Isotope Effect and Ferroelectric Transition in Quantum Paraelectrics","authors":"E. Matsushita, S. Segawa","doi":"10.1109/ISAF.2007.4393235","DOIUrl":"https://doi.org/10.1109/ISAF.2007.4393235","url":null,"abstract":"By extending the soft-phonon theory, a quantum paraelectric(PE)-ferroelectric(FE) transition in SrTi<sup>16</sup>O<sub>3</sub> (ST016) is studied from the viewpoint of the important role of optical phonons in perovskite-oxides. In spite of intrinsic quantum fluctuation of large zero-point vibration induced from light O-atoms, the FE transition due to the O-isotope exchange <sup>16</sup>O<sub>1-x</sub> <sup>18</sup>O<sub>x</sub> is explained in a unified picture by combining with the applied pressure (or uniaxial stress) effect. The calculated T<sub>c</sub> as the function of x is compared with the experimental data in rather good agreement, and the origin of quantum paraelectricity in STO 16 is discussed in comparison with pressure effect in hydrogen-bonded ferroelectrics KH<sub>2</sub>PO<sub>4</sub> (KDP). As the result, it is suggested that quantum PE-FE transition with the critical exponent 1/2 at T<sub>c</sub>=0 where the FE transition will start, must be analyzed by a microscopic theory exceeding soft phonon theory.","PeriodicalId":321007,"journal":{"name":"2007 Sixteenth IEEE International Symposium on the Applications of Ferroelectrics","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133003085","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 : 2007-05-27DOI: 10.1109/ISAF.2007.4393295
S. Baba, H. Tsuda, J. Akedo
Film thickness dependence of ferroelectric and/or piezoelectric properties for PZT films directly deposited onto stainless-steel (SUS) substrates in actuator devices by CO2 laser-assisted aerosol deposition was investigated. Analysis of the optical spectroscopic data and experimental results of laser irradiation revealed that absorption of an CO2 laser wavelength by the film increased with increasing the film thickness. Dielectric constant, remanent polarization, and coercive field values of the film irradiated by the CO2 laser at an annealing temperature of 850degC increased with increasing the film thickness region of 5 to 30 mum. The dielectric constant, remanent polarization, and the coercive field values of the PZT film, which irradiated by the laser, with a thickness of over 25 mum directly deposited onto the SUS substrate were over 800 and 40 muC/cm2 and under 45 kV/cm, respectively. Whereas, a displacement as the piezoelectric property of a SUS-based actuator with the PZT film irradiated by the laser decreased with increasing the film thickness. Finally, the reason and some countermeasure of deterioration of the ferroelectric and/or piezoelectric properties and the displacement for the SUS-based actuators with the PZT film irradiated by the laser are discussed.
研究了CO2激光辅助气溶胶沉积法直接沉积在不锈钢(SUS)衬底上的PZT薄膜的铁电和/或压电性能对薄膜厚度的依赖关系。光谱学数据和激光辐照实验结果分析表明，薄膜对CO2激光波长的吸收随薄膜厚度的增加而增加。在850℃的退火温度下，CO2激光辐照薄膜的介电常数、剩余极化和矫顽场值随着薄膜厚度在5 ~ 30 μ m范围内的增大而增大。直接沉积在SUS衬底上的厚度大于25 μ m的PZT薄膜，其介电常数大于800 μ c /cm2，剩余极化值为40 μ c /cm2，矫顽力场值小于45 kV/cm。而当激光照射PZT薄膜时，位移作为作动器的压电性能随薄膜厚度的增加而减小。最后，讨论了激光照射压电薄膜后，sus_s_基作动器铁电性能和压电性能恶化的原因及对策。
{"title":"Laser Irradiation Effect of Film Thickness on the Properties of Aerosol Deposition-Derived PZT Films on Metal Substrate","authors":"S. Baba, H. Tsuda, J. Akedo","doi":"10.1109/ISAF.2007.4393295","DOIUrl":"https://doi.org/10.1109/ISAF.2007.4393295","url":null,"abstract":"Film thickness dependence of ferroelectric and/or piezoelectric properties for PZT films directly deposited onto stainless-steel (SUS) substrates in actuator devices by CO2 laser-assisted aerosol deposition was investigated. Analysis of the optical spectroscopic data and experimental results of laser irradiation revealed that absorption of an CO2 laser wavelength by the film increased with increasing the film thickness. Dielectric constant, remanent polarization, and coercive field values of the film irradiated by the CO2 laser at an annealing temperature of 850degC increased with increasing the film thickness region of 5 to 30 mum. The dielectric constant, remanent polarization, and the coercive field values of the PZT film, which irradiated by the laser, with a thickness of over 25 mum directly deposited onto the SUS substrate were over 800 and 40 muC/cm2 and under 45 kV/cm, respectively. Whereas, a displacement as the piezoelectric property of a SUS-based actuator with the PZT film irradiated by the laser decreased with increasing the film thickness. Finally, the reason and some countermeasure of deterioration of the ferroelectric and/or piezoelectric properties and the displacement for the SUS-based actuators with the PZT film irradiated by the laser are discussed.","PeriodicalId":321007,"journal":{"name":"2007 Sixteenth IEEE International Symposium on the Applications of Ferroelectrics","volume":"269 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134546328","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 : 2007-05-27DOI: 10.1109/ISAF.2007.4393330
C. Tu, C. Hsieh, C.-T. Tseng, F.-T. Wang, S. Lee, H. Chuang
This work presents electric-field-induced dielectric permittivity and depolarization in (001)-cut relaxor Pb(Mg1/3Nb2/3)0.70Ti0.30O3 (PMNT30%) and Pb(In1/2Nb1/2)0.70Ti0.30O3 (PINT30%) single crystals. The depolarization temperature Tdcong395 K of PINT30% is about 40 K higher than in the rhombohedral PMNT30%. The relaxor-type dielectric dispersion due to polar nanoclusters reappears above Td, and remains evident up to the Burns temperature.
{"title":"Electric-Field-Induced Dielectric Properties and Depolarization in Pb(Mg1/3Nb2/3)1-xTixO3 and Pb(In1/2Nb1/2)1-xTixO3 Crystals","authors":"C. Tu, C. Hsieh, C.-T. Tseng, F.-T. Wang, S. Lee, H. Chuang","doi":"10.1109/ISAF.2007.4393330","DOIUrl":"https://doi.org/10.1109/ISAF.2007.4393330","url":null,"abstract":"This work presents electric-field-induced dielectric permittivity and depolarization in (001)-cut relaxor Pb(Mg<sub>1/3</sub>Nb<sub>2/3</sub>)<sub>0.70</sub>Ti<sub>0.30</sub>O<sub>3</sub> (PMNT30%) and Pb(In<sub>1/2</sub>Nb<sub>1/2</sub>)<sub>0.70</sub>Ti<sub>0.30</sub>O<sub>3</sub> (PINT30%) single crystals. The depolarization temperature T<sub>d</sub>cong395 K of PINT30% is about 40 K higher than in the rhombohedral PMNT30%. The relaxor-type dielectric dispersion due to polar nanoclusters reappears above T<sub>d</sub>, and remains evident up to the Burns temperature.","PeriodicalId":321007,"journal":{"name":"2007 Sixteenth IEEE International Symposium on the Applications of Ferroelectrics","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131967596","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 : 2007-05-27DOI: 10.1109/ISAF.2007.4393319
M. Nakada, K. Ohashi, H. Tsuda, E. Kawate, J. Akedo
The dielectric properties of lead zirconate titanate [PZT, Pb(Zr0.3Ti0.7)O3] films, prepared by aerosol deposition (AD), were measured in the millimeter wave and THz range. Millimeter wave spectroscopy was applied for measurement in the frequency range from 45 to 80 GHz, and far-infrared Fourier transform measurements from 120 GHz to 20 THz was carried out. Spectroscopic data were analyzed with combination of Debye model with a distribution of Debye relaxation frequencies and harmonic oscillators. We clearly observed that the Debye relaxation took place below several tens GHz for annealed AD films. Combination of millimeter wave and THz spectroscopy was effective measurement technique for dielectric properties of ferroelectric materials at over millimeter wave range.
{"title":"Dielectric Characteristics of PZT Films Prepared by Aerosol Deposition in Millimeter Wave Range","authors":"M. Nakada, K. Ohashi, H. Tsuda, E. Kawate, J. Akedo","doi":"10.1109/ISAF.2007.4393319","DOIUrl":"https://doi.org/10.1109/ISAF.2007.4393319","url":null,"abstract":"The dielectric properties of lead zirconate titanate [PZT, Pb(Zr0.3Ti0.7)O3] films, prepared by aerosol deposition (AD), were measured in the millimeter wave and THz range. Millimeter wave spectroscopy was applied for measurement in the frequency range from 45 to 80 GHz, and far-infrared Fourier transform measurements from 120 GHz to 20 THz was carried out. Spectroscopic data were analyzed with combination of Debye model with a distribution of Debye relaxation frequencies and harmonic oscillators. We clearly observed that the Debye relaxation took place below several tens GHz for annealed AD films. Combination of millimeter wave and THz spectroscopy was effective measurement technique for dielectric properties of ferroelectric materials at over millimeter wave range.","PeriodicalId":321007,"journal":{"name":"2007 Sixteenth IEEE International Symposium on the Applications of Ferroelectrics","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133744002","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 : 2007-05-27DOI: 10.1109/ISAF.2007.4393393
Pei-Yen Chen, Y. Chin, Chi-Yun Chen, Chun-Li Hou
This paper presents improved formula accuracy for quality factor Q of thin film bulk acoustic resonators (FBARs) with close series and parallel resonance frequencies. Traditionally, the series and parallel resonance behaviors are treated independently. The FBAR piezoelectric coupling coefficient is only a few percentages with the series and parallel frequencies close enough to influence each other. The FBARs with two-port configuration are fabricated using silicon bulk micro-machining technology. Including the FBAR transmission lines are analyzed to probe their characteristics using a network analyzer. The signal power loss of the transmission lines is modeled to characterize the FBARs using two-port S parameter measurement data.
{"title":"Accurate Formula for Quality Factor Q of Thin Film Bulk Acoustic Resonators with Close Series and Parallel Resonance Frequencies","authors":"Pei-Yen Chen, Y. Chin, Chi-Yun Chen, Chun-Li Hou","doi":"10.1109/ISAF.2007.4393393","DOIUrl":"https://doi.org/10.1109/ISAF.2007.4393393","url":null,"abstract":"This paper presents improved formula accuracy for quality factor Q of thin film bulk acoustic resonators (FBARs) with close series and parallel resonance frequencies. Traditionally, the series and parallel resonance behaviors are treated independently. The FBAR piezoelectric coupling coefficient is only a few percentages with the series and parallel frequencies close enough to influence each other. The FBARs with two-port configuration are fabricated using silicon bulk micro-machining technology. Including the FBAR transmission lines are analyzed to probe their characteristics using a network analyzer. The signal power loss of the transmission lines is modeled to characterize the FBARs using two-port S parameter measurement data.","PeriodicalId":321007,"journal":{"name":"2007 Sixteenth IEEE International Symposium on the Applications of Ferroelectrics","volume":" 27","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133052038","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 : 2007-05-27DOI: 10.1109/ISAF.2007.4393196
F. Chang, Sean Wu, Maw-Shung Lee, Jianwei Yu, Chiaokai Chang, Chengxiong Huang
Highly (002) oriented aluminum nitride (AlN) films were successfully prepared on a 64deg-YX LiNbO3 substrate by r.f. magnetron sputtering. The crystalline structure of the films was determined by grazing incident angle X-ray diffraction (XRD) and the surface microstructure of films was investigated by Scanning electron microscope (SEM). The atom composition ratio (Al/N) of the films was also determined by Energy Dispersive X-ray Spectroscopy (EDS). The results showed the optimal (002) oriented AlN films were prepared at 200 C and 5 m Torr. The atom composition ratio (Al/N) was 0.96 (near 1).
{"title":"Crystalline Structure and Surface Morphology of the AlN films sputtered on 64°-YX LiNbO3","authors":"F. Chang, Sean Wu, Maw-Shung Lee, Jianwei Yu, Chiaokai Chang, Chengxiong Huang","doi":"10.1109/ISAF.2007.4393196","DOIUrl":"https://doi.org/10.1109/ISAF.2007.4393196","url":null,"abstract":"Highly (002) oriented aluminum nitride (AlN) films were successfully prepared on a 64deg-YX LiNbO3 substrate by r.f. magnetron sputtering. The crystalline structure of the films was determined by grazing incident angle X-ray diffraction (XRD) and the surface microstructure of films was investigated by Scanning electron microscope (SEM). The atom composition ratio (Al/N) of the films was also determined by Energy Dispersive X-ray Spectroscopy (EDS). The results showed the optimal (002) oriented AlN films were prepared at 200 C and 5 m Torr. The atom composition ratio (Al/N) was 0.96 (near 1).","PeriodicalId":321007,"journal":{"name":"2007 Sixteenth IEEE International Symposium on the Applications of Ferroelectrics","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114071773","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 : 2007-05-27DOI: 10.1109/ISAF.2007.4393194
H. Uchida, K. Nishida, M. Osada, Funakubo, S. Koda
Thin films of Bi-based perovskite ferroelectrics BiFeO3 is recently recognized as strong candidates for alternatives to toxic Pb-based ferroelectrics such as conventional Pb(Zr,Ti)O3. Authors fabricated BiFeO3 thin films with excellent performance of ferroelectric polarization by ion modification based on sol-gel technique. Some rare-earth ions, such as La3+ or Nd3+, could be substituted for Bi3+ ion in BFO crystal in order to reduce ionic defects in crystal lattices. Electrical resistivity of BiFeO3 films were improved by ion modification of rare-earth elements, as well as other Bi-based ferroelectric films like Bi4Ti3O12. Although crystal anisotropy and phase-transition temperature (Curie temperature) of these materials are generally reduced by the ion modification, it yield fully-saturated polarization (P) -electrical field (E) property to produce enhanced remanent polarization of approximately 50 muC/cm comparable or superior to conventional Pb(Zr,Ti)O3 films. We concluded that the ion modification using rare-earth elements could suppress the ionic defects that caused electrical conduction in BiFeO3 films.
{"title":"Bi-based ferroelectric thin films with enhanced polarization by rare-earth modification","authors":"H. Uchida, K. Nishida, M. Osada, Funakubo, S. Koda","doi":"10.1109/ISAF.2007.4393194","DOIUrl":"https://doi.org/10.1109/ISAF.2007.4393194","url":null,"abstract":"Thin films of Bi-based perovskite ferroelectrics BiFeO<sub>3</sub> is recently recognized as strong candidates for alternatives to toxic Pb-based ferroelectrics such as conventional Pb(Zr,Ti)O<sub>3</sub>. Authors fabricated BiFeO<sub>3</sub> thin films with excellent performance of ferroelectric polarization by ion modification based on sol-gel technique. Some rare-earth ions, such as La<sup>3+</sup> or Nd<sup>3+</sup>, could be substituted for Bi<sup>3+</sup> ion in BFO crystal in order to reduce ionic defects in crystal lattices. Electrical resistivity of BiFeO<sub>3</sub> films were improved by ion modification of rare-earth elements, as well as other Bi-based ferroelectric films like Bi<sub>4</sub>Ti<sub>3</sub>O<sub>12</sub>. Although crystal anisotropy and phase-transition temperature (Curie temperature) of these materials are generally reduced by the ion modification, it yield fully-saturated polarization (P) -electrical field (E) property to produce enhanced remanent polarization of approximately 50 muC/cm comparable or superior to conventional Pb(Zr,Ti)O<sub>3</sub> films. We concluded that the ion modification using rare-earth elements could suppress the ionic defects that caused electrical conduction in BiFeO<sub>3</sub> films.","PeriodicalId":321007,"journal":{"name":"2007 Sixteenth IEEE International Symposium on the Applications of Ferroelectrics","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114784070","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 : 2007-05-27DOI: 10.1109/ISAF.2007.4393229
Do Doc Cuong, Seungwu Han, Jaichan Leela
Oxygen vacancy in SrTiO3 is studied using the first principles calculation with the correction of onsite Coulomb interaction. In this paper, we performed the calculations on the multi oxygen vacancies in typical perovskite SrTiO3. We found that the oxygen vacancies tend to cluster in a linear way which makes the reduction of electron carrier concentration.
{"title":"First principles study on oxygen vacancies in SrTiO3","authors":"Do Doc Cuong, Seungwu Han, Jaichan Leela","doi":"10.1109/ISAF.2007.4393229","DOIUrl":"https://doi.org/10.1109/ISAF.2007.4393229","url":null,"abstract":"Oxygen vacancy in SrTiO3 is studied using the first principles calculation with the correction of onsite Coulomb interaction. In this paper, we performed the calculations on the multi oxygen vacancies in typical perovskite SrTiO3. We found that the oxygen vacancies tend to cluster in a linear way which makes the reduction of electron carrier concentration.","PeriodicalId":321007,"journal":{"name":"2007 Sixteenth IEEE International Symposium on the Applications of Ferroelectrics","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131778829","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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