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Full-Text Articles in Physics

Microimprinting And Ferroelectric Properties Of Poly(Vinylidene Fluoride-Trifluoroethylene) Copolymer Films, Lei Zhang, Stephen Ducharme, Jiangyu Li Oct 2007

Microimprinting And Ferroelectric Properties Of Poly(Vinylidene Fluoride-Trifluoroethylene) Copolymer Films, Lei Zhang, Stephen Ducharme, Jiangyu Li

Stephen Ducharme Publications

Poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] copolymer films have been patterned by microimprinting with excellent quality of pattern transferring. Ferroelectricity of the imprinted films has been confirmed by ferroelectric hysteresis and surface potential measurement, and very good correlation is observed between remnant polarization and surface potential of the imprinted films. Imprinted P(VDF-TrFE) films show high remnant polarization and high poling-induced surface potential when the imprinting temperature is around 140 °C, suggesting that 140 °C is the optimal imprinting temperature for P(VDF-TrFE) films. The patterned ferroelectric P(VDF-TrFE) films can be used for a wide range of applications.


Vitaly Ginzburg: The Last Classical Physicist, Vladimir Fridkin, Stephen Ducharme, Wolfgang Kleemann, Yoshihiro Ishibashi Sep 2007

Vitaly Ginzburg: The Last Classical Physicist, Vladimir Fridkin, Stephen Ducharme, Wolfgang Kleemann, Yoshihiro Ishibashi

Stephen Ducharme Publications

It is a great honor and responsibility to be Guest Editors for the special issue of Ferroelectrics, dedicated to the 90th Birthday of Nobel Prize Winner Prof. Vitaly Ginzburg. We have entitled our Guest Editorial “The Last Classical Physicist” because his creative work practically covers all regions of the modern physics: astronomy, astrophysics, cosmic rays, high spin elementary particles, quantum electrodynamics, solid state physics, including superconductivity and superfluidity, superdiamagnetism and ferrotoroics, crystallooptics and last (but for this journal not least) the theory of ferroelectricity and soft mode conception.


Electron Diffraction Study Of The Structure Of Vinylidene Fluoride–Trifluoroethylene Copolymer Nanocrystals, Mengjun Bai, Xingzhong Li, Stephen Ducharme Apr 2007

Electron Diffraction Study Of The Structure Of Vinylidene Fluoride–Trifluoroethylene Copolymer Nanocrystals, Mengjun Bai, Xingzhong Li, Stephen Ducharme

Stephen Ducharme Publications

The structures of nanocrystals consisting of 70% vinylidene fluoride and 30% trifluoroethylene made by Langmuir–Blodgett deposition were studied using transmission electron microscopy and electron diffraction. Highly ordered nanocrystals with sizes ranging from 100 nm to 4 μm were grown on Langmuir– Blodgett films at a deposition surface pressure of 20 mN m-1. Electron diffraction patterns from individual crystals allowed us to determine the crystal symmetry and lattice parameters. A monoclinic phase had been found with the lattice parameters a = 9.06 ± 0.03 Å, b = 5.18 ± 0.02 Å, c = 20.40 ± 0.05 Å, α = 90 ...


Electric Energy Density Of Dielectric Nanocomposites, Jiangyu Li, L. Zhang, Stephen Ducharme Mar 2007

Electric Energy Density Of Dielectric Nanocomposites, Jiangyu Li, L. Zhang, Stephen Ducharme

Stephen Ducharme Publications

Dielectric materials with large electric energy density are actively pursued for many applications. The authors analyze the effective permittivity, breakdown strength, and electric energy density of dielectric nanocomposites using an effective medium approximation, modeling the nanocomposite as a three-phase material by the double-inclusion method. The addition of nanoparticles enhances the permittivity but reduces the breakdown strength, making the potential gain in electric energy density small. In addition, the interfacial interaction shifts the “percolation” threshold toward lower volume fraction of nanoparticles. The analysis suggests that the microstructure of nanocomposites must be carefully controlled to maintain high dielectric strength and therefore realize ...


Nanoscale Polarization Manipulation And Imaging Of Ferroelectric Langmuir-Blodgett Polymer Films, Brian J. Rodriguez, Stephen Jesse, Sergei V. Kalinin, Jihee Kim, Stephen Ducharme, V.M. Fridkin Mar 2007

Nanoscale Polarization Manipulation And Imaging Of Ferroelectric Langmuir-Blodgett Polymer Films, Brian J. Rodriguez, Stephen Jesse, Sergei V. Kalinin, Jihee Kim, Stephen Ducharme, V.M. Fridkin

Stephen Ducharme Publications

Piezoresponse force microscopy has been used to manipulate and image polarization of ferroelectric polymer Langmuir-Blodgett films at the nanoscale, achieving polarization control with a resolution below 50 nm and imaging resolution below 5 nm. Individual regions showed square polarization-voltage hysteresis loops, demonstrating bistability of the polarization state. Arbitrary polarization patterns could be repeatedly written and erased with a resolution of 25 to 50 nm, limited by grain size, demonstrating the potential for high-density data storage and retrieval at densities exceeding 250 Gbits/ in2.


The Effect Of Interlayer Interactions On The Ferroelectric–Paraelectric Phase Transition In Multilayered Thin Films Of Vinylidene Fluoride–Trifluoroethylene Copolymers, Jihee Kim, Hoydoo You, Stephen Ducharme, Shireen Adenwalla Feb 2007

The Effect Of Interlayer Interactions On The Ferroelectric–Paraelectric Phase Transition In Multilayered Thin Films Of Vinylidene Fluoride–Trifluoroethylene Copolymers, Jihee Kim, Hoydoo You, Stephen Ducharme, Shireen Adenwalla

Stephen Ducharme Publications

The interaction between ferroelectric polymer films with different transition temperatures is evident in the effect of layer thickness on the ferroelectric– paraelectric phase transition in multilayer films, as revealed by x-ray diffraction and dielectric measurements. The multilayer samples consisted of alternating Langmuir–Blodgett (LB) films of two different copolymers of vinylidene fluoride with trifluoroethylene, one with 80% vinylidene fluoride and a ferroelectric–paraelectric transition temperature on heating of 133 ± 4 °C and the other with 50% vinylidene fluoride and a transition temperature of 70 ± 4 °C. Samples with a repeat period of 20 LB layers (10 contiguous layers of each ...


The Effect Of Interlayer Interactions On The Ferroelectric–Paraelectric Phase Transition In Multilayered Thin Films Of Vinylidene Fluoride– Trifluoroethylene Copolymers, Jihee Kim, Hoydoo You, Stephen Ducharme, Shireen Adenwalla Feb 2007

The Effect Of Interlayer Interactions On The Ferroelectric–Paraelectric Phase Transition In Multilayered Thin Films Of Vinylidene Fluoride– Trifluoroethylene Copolymers, Jihee Kim, Hoydoo You, Stephen Ducharme, Shireen Adenwalla

Stephen Ducharme Publications

The interaction between ferroelectric polymer films with different transition temperatures is evident in the effect of layer thickness on the ferroelectric– paraelectric phase transition in multilayer films, as revealed by x-ray diffraction and dielectric measurements. The multilayer samples consisted of alternating Langmuir–Blodgett (LB) films of two different copolymers of vinylidene fluoride with trifluoroethylene, one with 80% vinylidene fluoride and a ferroelectric– paraelectric transition temperature on heating of 133 ± 4 °C and the other with 50% vinylidene fluoride and a transition temperature of 70 ± 4 °C. Samples with a repeat period of 20 LB layers (10 contiguous layers of each ...


Ferroelectric Properties Of Langmuir-Blodgett Copolymer Films At The Nanoscale, A. Tolstousov, R. V. Gaynutdinov, R. Tadros-Morgane, Herbert Kliem, Stephen Ducharme, Vladimir M. Fridkin Jan 2007

Ferroelectric Properties Of Langmuir-Blodgett Copolymer Films At The Nanoscale, A. Tolstousov, R. V. Gaynutdinov, R. Tadros-Morgane, Herbert Kliem, Stephen Ducharme, Vladimir M. Fridkin

Stephen Ducharme Publications

Langmuir-Blodgett (LB) films are well known structures prepared as a result of successive transfer of monolayers (ML) from the gas-liquid interface onto solid substrates. One impressive possibility of LB method is the opportunity to vary the thickness of the film to an accuracy of one transfer, which could coincide with one ML. The ferroelectric properties of a copolymer of vinylidene fluoride and trifluorethylene P[VDF-TrFE] prepared by LB deposition are investigated in the region of a few monolayers.