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Full-Text Articles in Physics
Effect Of Thermal Annealing On Ferroelectric Domain Structures In Poly(Vinylidene-Fluoride-Trifluorethylene) Langmuir-Blodgett Thin Films, Zhiyong Xiao, J. Hamblin, Shashi Poddar, Stephen Ducharme, P. Paruch, Xia Hong
Effect Of Thermal Annealing On Ferroelectric Domain Structures In Poly(Vinylidene-Fluoride-Trifluorethylene) Langmuir-Blodgett Thin Films, Zhiyong Xiao, J. Hamblin, Shashi Poddar, Stephen Ducharme, P. Paruch, Xia Hong
Stephen Ducharme Publications
We report a piezo-response force microscopy study of the effect of thermal annealing on ferroelectric domain structures in 6 to 20 monolayer (11 to 36 nm) polycrystalline poly(vinylidene-fluoridetrifluorethylene) thin films prepared using the Langmuir-Blodgett approach. Stripe-shape domains have been created at room temperature and subjected to thermal annealing at progressively higher temperatures up to the ferroelectric Curie temperature TC of approximately 110 °C. The static configuration of the domain walls exhibits no appreciable temperature dependence after thermal annealing, with the domain-wall roughness exponent ζ ranging from 0.4 to 0.5. Above 80 °C, we observed spontaneous polarization reversal at randomly …
Investigation Of Ferroelectric Domains In Thin Films Of Vinylidene Fluoride Oligomers, Pankaj Sharma, Shashi Poddar, Rafal Korlacki, Stephen Ducharme, Alexei Gruverman
Investigation Of Ferroelectric Domains In Thin Films Of Vinylidene Fluoride Oligomers, Pankaj Sharma, Shashi Poddar, Rafal Korlacki, Stephen Ducharme, Alexei Gruverman
Stephen Ducharme Publications
High-resolution vector piezoresponse force microscopy (PFM) has been used to investigate ferroelectric domains in thin vinylidene fluoride oligomer films fabricated by the Langmuir-Blodgett deposition technique. Molecular chains are found to be preferentially oriented normal to the substrate, and PFM imaging shows that the films are in ferroelectric β-phase with a predominantly in-plane polarization, in agreement with infrared spectroscopic ellipsometry and X-ray diffraction measurements. The fractal analysis of domain structure has yielded the Hausdorff dimension (D) in the range of ~1.3–1.5 indicating a random-bond nature of the disorder potential, with domain size exhibiting Landau-Lifshitz-Kittel scaling.
Polarization Imaging In Ferroelectric Polymer Thin Film Capacitors By Pyroelectric Scanning Microscopy, Jingfeng Song, Haidong Lu, Alexei Gruverman, Stephen Ducharme
Polarization Imaging In Ferroelectric Polymer Thin Film Capacitors By Pyroelectric Scanning Microscopy, Jingfeng Song, Haidong Lu, Alexei Gruverman, Stephen Ducharme
Stephen Ducharme Publications
A Pyroelectric Scanning Microscopy system, which uses laser-induced thermal modulation for mapping the pyroelectric response, has been used to image a bipolar domain pattern in a ferroelectric polymer thin film capacitor. This system has achieved a resolution of 660±28 nm by using a violet laser and high f-number microscope objective to reduce the optical spot size, and by operating at high modulation frequencies to reduce the thermal diffusion length. The results agree well with a thermal model implemented numerically using finite element analysis.
Temperature Dependence Of Flexoelectric Response In Ferroelectric And Relaxor Polymer Thin Films, Shashi Poddar, Stephen Ducharme
Temperature Dependence Of Flexoelectric Response In Ferroelectric And Relaxor Polymer Thin Films, Shashi Poddar, Stephen Ducharme
Stephen Ducharme Publications
We report the temperature dependence of the flexoelectric response in thin films of both ferroelectric and relaxor forms of vinylidene fluoride polymers. The ferroelectric samples were depoled to minimize piezoelectric response by heating them beyond their Curie temperature and then cooling in zero applied electric field. In both the relaxor ferroelectric polymer and the paraelectric state of the ferroelectric copolymer, the flexoelectric coefficient was proportional to the dielectric constant over a limited range of temperatures, in agreement with general theoretical principles. The enhancements in flexoelectric response were also observed near the Curie transition temperature for the ferroelectric polymer and near …
Ferroelectricity At The Nanoscale, Vladimir M. Fridkin, Stephen Ducharme
Ferroelectricity At The Nanoscale, Vladimir M. Fridkin, Stephen Ducharme
Stephen Ducharme Publications
The properties of ferroelectrics at the nanoscale are reviewed. The term nanoscale is here related to the ferroelectric film thickness (which is by an order of magnitude the size of the critical domain nucleus). The three aspects considered are ferroelectric switching, the scaling of the coercive field, and the bulk photovoltaic effect. While ferroelectricity at the nanoscale has a twenty-year history of study, it is only in the last few years that perovskite ferroelectric films have become a focus of interest.
The Ferroelectricity At The Nanoscale, Vladimir M. Fridkin, Stephen Ducharme
The Ferroelectricity At The Nanoscale, Vladimir M. Fridkin, Stephen Ducharme
Stephen Ducharme Publications
The review of ferroelectric properties at the nanoscale is presented. Determining the nanoscale, authors bear in mind the film thickness equal by the order of value to the size of critical domain nucleus. Three phenomena are considered: ferroelectric switching, scaling of coercive field and bulk photovoltaic effect. The investigation of ferroelectricity at the nanoscale started 20 years ago. The nanoscaled ferroelectricics with perovskite structure came to be considered only the last few years.
Laboratory Manual For Physics Of Lasers And Modern Optics, 13th Ed, Stephen Ducharme
Laboratory Manual For Physics Of Lasers And Modern Optics, 13th Ed, Stephen Ducharme
Stephen Ducharme Publications
You will encounter challenging puzzles and explore new and exciting physical phenomena. You will be provided with sufficient tools, guidance and other resources, but what you learn depends on your inquisitiveness and creativity. This laboratory course is designed to serve two purposes: 1) To explore a variety of physical principles using the fascinating and diverse behavior of light. 2) To learn some of the principles behind the pervasive and expanding area of optical and laser technology. This course is suitable for students of science, life sciences, and engineering, or any student who is curious about light. The prerequisites are the …
Coplanar Switching Of Polarization In Thin Films Of Vinylidene Fluoride Oligomers, Pankaj Sharma, Alexandra Fursina, Shashi Poddar, Stephen Ducharme, Alexei Gruverman
Coplanar Switching Of Polarization In Thin Films Of Vinylidene Fluoride Oligomers, Pankaj Sharma, Alexandra Fursina, Shashi Poddar, Stephen Ducharme, Alexei Gruverman
Stephen Ducharme Publications
Switching characteristics of vinylidene fluoride oligomer thin films with molecular chains aligned normal to the substrate and exhibiting a preferential in-plane polarization have been investigated using coplanar geometry of inter-digital electrodes via high-resolution piezoresponse force microscopy. It has been shown that in-plane switching proceeds via non-180 rotation of dipoles mediated by non-stochastic nucleation, expansion, and coalescence of domains. Asgrown multidomain configuration is found to be strongly pinned aided by charged domain walls, and the electrically induced (in-plane) mono-domain states relax to the as-grown state. The observed coercive field (approximately 0.6 MV/m) is two to three orders of magnitude smaller than …