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 Ames Laboratory (4)
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 BiFeO3–PbZrO3–PbTiO3 (1)
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Articles 1  14 of 14
FullText Articles in Physics
Interaction Dynamics Between Ferroelectric And Antiferroelectric Domains In A Pbzro3Based Ceramic, Zhongming Fan, Fei Xue, Goknur Tutuncu, LongQing Chen, Xiaoli Tan
Interaction Dynamics Between Ferroelectric And Antiferroelectric Domains In A Pbzro3Based Ceramic, Zhongming Fan, Fei Xue, Goknur Tutuncu, LongQing Chen, Xiaoli Tan
Materials Science and Engineering Publications
The antiferroelectricferroelectric phase transition in PbZrO3based oxides is of both fundamental and practical importance. In ceramics in which such a transition readily occurs, the antiferroelectric and the ferroelectric phases often coexist in individual grains with a coherent interphase interface. In this work, the electric biasing in situ transmission electron microscopy technique is employed to directly observe a unique microstructural dynamic when ferroelectric and antiferroelectric domains are driven by a moderate electric field to interact. It is found that, under monotonic loading, the ferroelectric domain grows until it is blocked by the ferroelectricantiferroelectric interface. At the same time, a kink is ...
Mechanisms Of Enhanced Thermal Stability Of Polarization In LeadFree (Bi 1/2na 1/2) 0.94ba 0.06tio 3/Zno Ceramic Composites, Zhongming Fan, Lin Zhou, TaeHoon Kim, Ji Zhang, ShanTao Zhang, Xiaoli Tan
Mechanisms Of Enhanced Thermal Stability Of Polarization In LeadFree (Bi 1/2na 1/2) 0.94ba 0.06tio 3/Zno Ceramic Composites, Zhongming Fan, Lin Zhou, TaeHoon Kim, Ji Zhang, ShanTao Zhang, Xiaoli Tan
Ames Laboratory Accepted Manuscripts
(Bi 1/2Na 1/2)TiO 3based solid solutions, one of the major systems of leadfree piezoelectric ceramics, exhibit a low thermal depolarization temperature ( T d~100°C). It was reported that by incorporating 30 mol% ZnO particles to form a ceramic composite of (Bi 1/2Na 1/2) 0.94Ba 0.06TiO 3/ZnO, the depolarization process can be shifted up to ~250 °C. In the present work, a variety of advanced transmission electron microscopy techniques, including in situ heating, annular brightfield, highangle annular darkfield, geometric phase analysis, energydispersive spectrum and electron energyloss spectroscopy, are employed to investigate the ...
Relation Of ShortRange And LongRange Lithium Ion Dynamics In GlassCeramics: Insights From Li7 Nmr FieldCycling And FieldGradient Studies, Michael Haaks, Steve W. Martin, Michael Vogel
Relation Of ShortRange And LongRange Lithium Ion Dynamics In GlassCeramics: Insights From Li7 Nmr FieldCycling And FieldGradient Studies, Michael Haaks, Steve W. Martin, Michael Vogel
Materials Science and Engineering Publications
We use various Li7 NMR methods to investigate lithium ion dynamics in 70Li(2)S30P(2)S(5) glass and glassceramic obtained from this glass after heat treatment. We employ Li7 spinlattice relaxometry, including fieldcycling measurements, and lineshape analysis to investigate shortrange ion jumps as well as Li7 fieldgradient approaches to characterize longrange ion diffusion. The results show that ceramization substantially enhances the lithium ion mobility on all length scales. For the 70Li(2)S30P(2)S(5) glassceramic, no evidence is found that bimodal dynamics result from different ion mobilities in glassy and crystalline regions of this sample. Rather ...
The Morphotropic Phase Boundary In The (1X)Pbzro3–X[0.3bi(Zn1/2ti1/2)O3–0.7pbtio3] Perovskite Solid Solution, T. Sareein, W. Hu, Xiaoli Tan, R. Yimnirun
The Morphotropic Phase Boundary In The (1X)Pbzro3–X[0.3bi(Zn1/2ti1/2)O3–0.7pbtio3] Perovskite Solid Solution, T. Sareein, W. Hu, Xiaoli Tan, R. Yimnirun
Materials Science and Engineering Publications
Ceramics in the (1x)PbZrO3–x[0.3Bi(Zn1/2Ti1/2)O3–0.7PbTiO3] solid solution system with 0.48 x 0.56 were investigated. A morphotropic phase boundary separating rhombohedral and tetragonal perovskite phases was identified at x = 0.52. This composition displays the maximum remanent polarization Pr of 40.7 μC/cm2 and the best piezoelectric coefficient d33 of 311 pC/N in the pseudobinary system. However, the Curie temperature Tc for this MPB composition is 291 °C, much lower than initially expected.
Nmr And Conductivity Studies Of The Mixed Glass Former Effect In Lithium Borophosphate Glasses, Michael Storek, Roland Böhmer, Steve W. Martin, Dirk Larink, Hellmut Eckert
Nmr And Conductivity Studies Of The Mixed Glass Former Effect In Lithium Borophosphate Glasses, Michael Storek, Roland Böhmer, Steve W. Martin, Dirk Larink, Hellmut Eckert
Materials Science and Engineering Publications
Alkali ion charge transport has been studied in a series of mixed glass former lithium borophosphate glasses of composition 0.33Li_{2}O + 0.67[xB_{2}O_{3} + (1 – x)P_{2}O_{5}]. The entire concentration range, 0.0 ≤ x ≤ 1.0, from pure glassy Li_{2}P_{4}O_{11} to pure glassy Li_{2}B_{4}O_{7} has been examined while keeping the molar fraction of Li_{2}O constant. Electrical conductivity measurements and nuclear magnetic resonance techniques such as spin relaxometry, line shape analysis, and stimulatedecho spectroscopy were used to examine the temperature ...
Spatially Resolved Distribution Function And The MediumRange Order In Metallic Liquid And Glass, X. W. Fang, CaiZhuang Wang, S. G. Hao, Matthew J. Kramer, Yongxin Yao, Mikhail I. Mendelev, Z. J. Ding, Ralph E. Napolitano, KaiMing Ho
Spatially Resolved Distribution Function And The MediumRange Order In Metallic Liquid And Glass, X. W. Fang, CaiZhuang Wang, S. G. Hao, Matthew J. Kramer, Yongxin Yao, Mikhail I. Mendelev, Z. J. Ding, Ralph E. Napolitano, KaiMing Ho
Materials Science and Engineering Publications
The structural description of disordered systems has been a longstanding challenge in physical science. We propose an atomic cluster alignment method to reveal the development of threedimensional topological ordering in a metallic liquid as it undercools to form a glass. By analyzing molecular dynamic (MD) simulation trajectories of a Cu64.5Zr35.5 alloy, we show that mediumrange order (MRO) develops in the liquid as it approaches the glass transition. Specifically, around Cu sites, we observe “Bergman triacontahedron” packing (icosahedron, dodecahedron and icosahedron) that extends out to the fourth shell, forming an interpenetrating backbone network in the glass. The discovery of ...
Piezoelectric Ceramics With Compositions At The Morphotropic Phase Boundary In The Bifeo3–Pbzro3–Pbtio3 Ternary System, Wei Hu, Xiaoli Tan, Krishna Rajan
Piezoelectric Ceramics With Compositions At The Morphotropic Phase Boundary In The Bifeo3–Pbzro3–Pbtio3 Ternary System, Wei Hu, Xiaoli Tan, Krishna Rajan
Materials Science and Engineering Publications
Since ceramics in the PbZrO_{3}–PbTiO_{3} binary system display excellent piezoelectric properties and those in BiFeO_{3}–PbTiO_{3} exhibit high Curie temperatures, morphotropic phase boundary (MPB) compositions in the BiFeO_{3}–PbZrO_{3}–PbTiO_{3} ternary solid solution system are investigated for the development of piezoelectric ceramics for high temperature applications. It is found that the MPB compositions in the ternary system deviate away from the mixture of two binary MPB compositions 0.70BiFeO_{3}–0.30PbTiO_{3} and 0.52PbZrO_{3}–0.48PbTiO_{3}. With decreasing amount of BiFeO_{3} in the MPB compositions in the ...
Compositional Disorder, Polar Nanoregions And Dipole Dynamics In Pb(Mg1/3nb2/3)O3Based Relaxor Ferroelectrics, Alexei A. Bokov, Brian J. Rodriguez, Xiaohui Zhao, JaeHyeon Ko, Stephen Jesse, Xifa Long, Weiguo Qu, Tae Hyun Kim, John D. Budai, Anna N. Morozovska, Seiji Kojima, Xiaoli Tan, Sergei V. Kalinin, ZuoGuang Ye
Compositional Disorder, Polar Nanoregions And Dipole Dynamics In Pb(Mg1/3nb2/3)O3Based Relaxor Ferroelectrics, Alexei A. Bokov, Brian J. Rodriguez, Xiaohui Zhao, JaeHyeon Ko, Stephen Jesse, Xifa Long, Weiguo Qu, Tae Hyun Kim, John D. Budai, Anna N. Morozovska, Seiji Kojima, Xiaoli Tan, Sergei V. Kalinin, ZuoGuang Ye
Materials Science and Engineering Publications
The complex structure of relaxor ferroelectrics comprises polar nanoregions (PNRs) which appear upon cooling below the Burns temperature and quenched compositional (chemical) disorder. The relation between the polar nanostructure and compositionally ordered regions (CORs) often observed in relaxors has been the subject of extensive theoretical investigations; however, the experimental data, especially concerning Pb(B′1/3B″2/3)O3type complex perovskite relaxors, are rather limited. In this paper, we analyse and discuss the results of our recent investigations of the morphology of CORs and the dynamics of PNRs in Pb(Mg1/3Nb2/3)O3 based solid solutions in which the ...
Relaxation In Glassforming Liquids And Amorphous Solids, C. Austin Angell, Kia L. Ngai, Greg B. Mckenna, Paul F. Mcmillan, Steve W. Martin
Relaxation In Glassforming Liquids And Amorphous Solids, C. Austin Angell, Kia L. Ngai, Greg B. Mckenna, Paul F. Mcmillan, Steve W. Martin
Materials Science and Engineering Publications
The field of viscousliquid and glassysolid dynamics is reviewed by a process of posing the key questions that need to be answered, and then providing the best answers available to the authors and their advisors at this time. The subject is divided into four parts, three of them dealing with behavior in different domains of temperature with respect to the glass transition temperature, Tg,and a fourth dealing with “short time processes.” The first part tackles the high temperature regime T>Tg, in which the system is ergodic and the evolution of the viscousliquid toward the condition at Tg is ...
Estimation Of The FreeChargeCarrier Concentration In FastIon Conducting Na2sB2s3 Glasses From An Analysis Of The FrequencyDependent, Ernest F. Hairetdinov, Nikolai F. Uvarov, Hitendra K. Patel, Steve W. Martin
Estimation Of The FreeChargeCarrier Concentration In FastIon Conducting Na2sB2s3 Glasses From An Analysis Of The FrequencyDependent, Ernest F. Hairetdinov, Nikolai F. Uvarov, Hitendra K. Patel, Steve W. Martin
Materials Science and Engineering Publications
ac and dc conductivities of fastion conducting xNa2S+(1x)B2S3 glasses in the composition range 0.001≤x≤0.1 were analyzed using the AlmondWest formula σ(ν)=σdc[1+(ν/νH)α]. The hopping frequency for free charge carriers νH, the dc conductivity σdc, and their respective activation energies were determined. The concentration of free charge carriers evaluated from the conductivities and estimated mobilities is in good agreement with the overall content of sodium cations in the glasses and it is proposed that this supports the concept of a strong and not weak electrolyte model for these ...
Correlation Functions For Ionic Motion From Nmr Relaxation And Electrical Conductivity In The Glassy FastIon Conductor (Li2s)0.56(Sis2)0.44, Ivar Svare, Ferdinando Borsa, D. R. Torgeson, Steve W. Martin
Correlation Functions For Ionic Motion From Nmr Relaxation And Electrical Conductivity In The Glassy FastIon Conductor (Li2s)0.56(Sis2)0.44, Ivar Svare, Ferdinando Borsa, D. R. Torgeson, Steve W. Martin
Materials Science and Engineering Publications
The Li7 NMR spinlattice relaxation and the electrical conductivity in the typical glassy fastion conductor (Li2S)0.56(SiS2)0.44 are discussed from models of Li+ionic motion with distributions of activation energies, as well as from stretchedexponential timecorrelation functions. The measured correlation times from the two effects differ by two orders of magnitude, and the derived distributions are shifted greatly relative to each other. We relate the great differences to percolation around the high barriers in the distribution. We present a phenomenological theory that yields good quantitative fits to the observed NMR relaxation with a Gaussian distribution, and ...
Relaxation And Fluctuations In Glassy FastIon Conductors: WideFrequencyRange Nmr And Conductivity Measurements, Ferdinando Borsa, D. R. Torgeson, Steve W. Martin, Hitendra K. Patel
Relaxation And Fluctuations In Glassy FastIon Conductors: WideFrequencyRange Nmr And Conductivity Measurements, Ferdinando Borsa, D. R. Torgeson, Steve W. Martin, Hitendra K. Patel
Materials Science and Engineering Publications
Li7 nuclear spinlattice relaxation rates (R1) versus the temperature at several resonance frequencies (4 to 40 MHz) are reported together with the conductivity measurements, σ(ω), in the range 1 Hz to 3.76 MHz on 0.56Li2S+0.44Si2S, a glassy fastionic conductor. Both R1 and σ(ω) are fitted consistently over the whole temperature and frequency range by using a stretchedexponential, i.e., exp(t/τ*c)β for the corresponding correlation functions (CF). Formulas that relate R1(ω) and σ(ω) and that give the asymptotic behavior as functions of T and ω of both quantities are ...
Correlation Between The Activation Enthalpy And Kohlrausch Exponent For Ionic Conductivity In Oxide Glasses, Kia L. Ngai, Steve W. Martin
Correlation Between The Activation Enthalpy And Kohlrausch Exponent For Ionic Conductivity In Oxide Glasses, Kia L. Ngai, Steve W. Martin
Materials Science and Engineering Publications
We have established for alkali ions in oxide glasses a strong correlation between the fractional (Kohlrausch) exponent β in the conductivity relaxation function, exp[(t/τ*)β], and the activation energy E*a of τ* and σ when varying the composition of oxide glass formers and the alkali ions while holding the alkaliion concentration constant. An even stronger correlation of the trends in β and the product βE*a is found. These correlations were expected conceptually by the coupling model for conductivity relaxation, and the latter was the motivation behind the present undertaking of the establishment of the correlation from ...
Thermal Conductivity Of Metals At High Temperatures, Paul H. Sidles, G. C. Danielson
Thermal Conductivity Of Metals At High Temperatures, Paul H. Sidles, G. C. Danielson
Ames Laboratory ISC Technical Reports
A new method of measuring thermal diffusivity and hence thermal conductivity of metals is suggested. Like previously reported dynamic methods, this method uses a heat source, whose temperature varies sinusoidally located at one end of an effectively infinite rod. Unlike these methods only one period of the heat wave is required to eliminate the unknown coefficient determining the heat lost by radiation since both velocity and amplitude decrement of the heat wave are measured. The new method is faster in taking data and simpler in computation. The thermoelectric potentials from two thermojunctions are amplified and plotted on a Brown "Electronic ...