| 1. |
- Abadei, Saeed, 1961, et al.
(författare)
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Low frequency characterisation of laser ablation deposited thin Na0.5K0.5NbO3 (NKN) films for microwave application
- 2001
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Ingår i: Integrated Ferroelectrics. - : Informa UK Limited. - 1058-4587 .- 1607-8489. ; 263:1, s. 173-179
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Tidskriftsartikel (refereegranskat)abstract
- Experimental results on three types of Na0.5K0.5NbO3 (NKN) film capacitor structures are presented. The epitaxial NKN thin films have been deposited on (100) Si (high resistivity), SiO2/Si (low resistivity) and Pt/Si (low resistivity) substrates using laser ablation deposition. Both straight slot and interdigital electrode have been deposited on top of the NKN films. The leakage current and low frequency dielectric properties (I-V, C-V, tanδ-V) of the structures have been measured at 1 MHz as a function of electric field at room temperature. In all three types of capacitor structures the leakage currents in a-b plane are very small, while along c-axis there are extremely large leakage currents. On low resistivity silicon substrates the tunability of the dielectric permittivity is about 12% and loss tangent is low also. On high resistivity (ρ>10 kOhm cm) silicon substrate the tunability at 1 MHz is extremely high, about 10 times, and the losses are also high. On the other hand at microwave frequencies the losses are small (tanδ
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| 2. |
- Benhouria, Y., et al.
(författare)
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Monte Carlo simulation of dielectric properties of a mixed spin-3/2 and spin-5/2 Ising ferrielectric nanowires
- 2017
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Ingår i: Ferroelectrics (Print). - : TAYLOR & FRANCIS LTD. - 0015-0193 .- 1563-5112. ; 507:1, s. 58-68
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Tidskriftsartikel (refereegranskat)abstract
- Dielectric properties of Ising ferrielectric nanowires with spin-3/2 core and spin-5/2 shell structure are systematically studied by the use of the Monte Carlo simulation in the presence of the external longitudinal electric field. Special focus is given to the effects of the core and shell interactions, the interface coupling and the temperature on the core and shell polarizations, the specific heat, the compensations points, the susceptibility and hysteresis behaviors. Some characteristic behaviors are found, such as the existence of triple hysteresis loops for appropriate values of the system parameters affected by the antiferroelectric interface coupling constant and the temperature. The results are compared with those of recently published works and a qualitatively good agreement is found.
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| 3. |
- Brunahl, J., et al.
(författare)
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Non-destructive pulsed technique to characterize functional properties of micromachined bulk PZT
- 2001
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Ingår i: Ferroelectrics (Print). - 0015-0193 .- 1563-5112. ; 263:1-4, s. 1487-1492
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Tidskriftsartikel (refereegranskat)abstract
- In this report, a non-destructive pulsed technique is presented to characterize all relevant properties of machined bulk PZT material. The proposed method is based on recording of the transient current as response on the short voltage pulse applied to the ferroelectric acoustic element. This new promising experimental technique makes it possible to measure mechanical and electrical properties fast, reliably and reproducibly. Among other results we can obtain electromechanical coupling coefficient, dielectric loss factor tan 8, mechanical quality factor Q, dielectric constant, capacitance, resonant frequency and Curie temperature T-c. The temperature dependence of above mentioned parameters can be studied as well very easily.
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| 4. |
- Canalias, Carlota, et al.
(författare)
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Periodic poling of KTiOPO4 : From micrometer to sub-micrometer domain gratings
- 2006
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Ingår i: Ferroelectrics (Print). - : Informa UK Limited. - 0015-0193 .- 1563-5112. ; 340:1, s. 27-47
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Tidskriftsartikel (refereegranskat)abstract
- Some novel techniques to do periodic poling of KTP are described. Emphasis on ways to avoid domain broadening and merging of domains is presented with reference to the original properties of flux grown KTP. For sub-Am structures E-beam lithography and deep UV-laser lithography were used to pattern the samples, and chemical process to promote selective poling to obtain high quality domain gratings in up to 1 mm thick samples.
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| 5. |
- Damm, Signe, et al.
(författare)
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Protein assemblies on ferroelectrically patterned microarrays of Ag nanoparticles
- 2017
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Ingår i: Ferroelectrics (Print). - : TAYLOR & FRANCIS LTD. - 0015-0193 .- 1563-5112. ; 515:1, s. 141-148
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Tidskriftsartikel (refereegranskat)abstract
- Nano-bio interfaces play a significant role in assay device design and performance, here we study the use of a combined plasmonic and ferroelectric active substrate design for protein assemblies on a plasmon active array. We demonstrate that biotinylation and protein assemblies can bemade onmetal nanoparticles patterned on ferroelectric substrates. These results inturndemonstratethat ferroelectric substrates combined with active plasmonics is potentially applicable as substrates for biological assays.
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| 6. |
- Frantti, J, et al.
(författare)
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Local and average structure of lead titanate based ceramics
- 2002
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Ingår i: Ferroelectrics. - : Informa UK Limited. - 0015-0193 .- 1563-5112. ; 266:1, s. 73-90
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Tidskriftsartikel (refereegranskat)abstract
- The revised lattice dynamics of Pb(Zr x Ti 1 -x )O 3 (PZT) with 0.10 ≤ x ≤0.54 ceramics is reported. The phase transition from tetragonal phase to the monoclinic phase is proposed to occur via locally distorted regions. Neutron diffraction data suggests that these local regions transform to the monoclinic phase with decreasing temperature, when x ≈0.50.
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| 7. |
- Gallo, Katia, et al.
(författare)
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Bidimensional Hexagonal Poling of LiNbO3 for Nonlinear Photonic Crystals and Quasi-Crystals
- 2006
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Ingår i: Ferroelectrics (Print). - : Informa UK Limited. - 0015-0193 .- 1563-5112. ; 340, s. 69-74
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Tidskriftsartikel (refereegranskat)abstract
- We report on the fabrication of bidimensional arrays of hexagonal domains with strictly periodic and quasi-periodic patterns for the implementation of nonlinear photonic crystals and quasi-crystals in z-cut congruent LiNbO3.
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| 8. |
- Hegde, Gurumurthy, 1979, et al.
(författare)
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Electrically controlled birefringent colors of Smectic C* Deformed Helix Ferroelectric Liquid
- 2008
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Ingår i: Ferroelectrics. - : Informa UK Limited. - 0015-0193 .- 1563-5112. ; 365
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Konferensbidrag (refereegranskat)abstract
- Short helix pitch (p0 = 0.45 μm) ferroelectric liquid crystal (FLC) mixture possessing high birefringenc under the action of applied voltage not more than 5 V provides four electrically switched birefringent colors: blue, green, yellow and red, while before only two [1] or three [2] colors were switched. Contrast ratio of birefringence colors were measured dependently on the driving voltage frequency. A possible application in field sequential color display where fast switching time is required has been proposed.
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| 9. |
- Hegde, Gurumurthy, 1979, et al.
(författare)
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“Inherent Continuous, Hysteretic Free and Memorized Gray Scale of FLC Display Cells Based
- 2008
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Ingår i: Ferroelectrics. - : Informa UK Limited. - 0015-0193 .- 1563-5112. ; 364
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Konferensbidrag (refereegranskat)abstract
- Ferroelectric liquid crystal (FLC) mixtures with high spontaneous polarization (Ps > 50 nC/cm2) possessing ferroelectric domains [1] exhibit a multistability effect which has been known for more than 10 years [2, 3]. Any light transmission level can be memorized in the effect after the driving voltage is switched off. The multistability effect is responsible for three new electrooptical modes with continuous, memorized and reversible gray scale. Depending on the asymmetry in boundary conditions and crystallooptical parameters of the cell, these modes differ among themselves under the shape of the gray scale curve that can be either S (double or single) or V-shaped. Origin of the phenomenon is under consideration here.
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| 10. |
- Hirohashi, Junji
(författare)
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Fabrication of 90-degree domain structures in KNbO3 single crystals
- 2003
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Ingår i: Ferroelectrics (Print). - 0015-0193 .- 1563-5112. ; 282, s. 29-36
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Tidskriftsartikel (refereegranskat)abstract
- New domain (90 domain) structure in the KNbO 3 single crystal could be fabricated by applying electric field at room temperature. The coercive electric field of 90 domain is very low (140 V/mm) compared with that of 180 domain (250 V/mm). A very sharp boundary was observed across the whole sample thickness (2 mm). Fabricated 90 domain structures were also confirmed by the (101) surface profile measurement using the optical interferrometer and two peaks of the 404 X-ray diffraction analysis. We also demonstrated the fabrication of periodically 90 domain structures with 200 μ m period without generating unwanted domain structures. As 90 domain structure feels the difference of the refractive index, new applications other than 180 domain will be possible.
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