Search

Your search keyword '"Micka Bah"' showing total 8 results
Start Over Author "Micka Bah" Publisher elsevier bv
8 results on '"Micka Bah"'

2. Study of the long time relaxation of the weak ferroelectricity in PbZrO3 antiferroelectric thin film using Positive Up Negative Down and First Order Reversal Curves measurements

Author

Kevin Nadaud, Caroline Borderon, Raphaël Renoud, Micka Bah, Stephane Ginestar, Hartmut W. Gundel, GREMAN (matériaux, microélectronique, acoustique et nanotechnologies) (GREMAN - UMR 7347), Université de Tours (UT)-Institut National des Sciences Appliquées - Centre Val de Loire (INSA CVL), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Institut d'Électronique et des Technologies du numéRique (IETR), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-Nantes Université - pôle Sciences et technologie, and Nantes Université (Nantes Univ)-Nantes Université (Nantes Univ)

Subjects
Positive up negative, Residual ferroelectricity, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Materials Chemistry, Metals and Alloys, Anti-ferroelectric, Thin film, Surfaces and Interfaces, [SPI.NANO]Engineering Sciences [physics]/Micro and nanotechnologies/Microelectronics, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials
Abstract

International audience; The weak ferroelectric contribution to the polarization of antiferroelectric lead zirconate (PZO) thin films has been investigated using PUND (Positive Up Negative Down) pulse measurements and hysterons decomposition by First Order Reversal Curves (FORC) technique. The PUND allows decomposing the measured current, obtained from the polarization-electric field loop measurements, into a switching and a non-switching contribution. We show that the weak ferroelectric phase is enhanced when a large electric field has been previously applied to the material, in order to switch from the antiferroelectric to the ferroelectric phase. Using the PUND measurement at fields below the antiferroelectric to ferroelectric phase transition, the polarization loop corresponding only to the ferroelectric switching contribution has been determined revealing that this contribution to the overall polarization is small. FORC measurements, however, indicate that the ferroelectric phase is present at different fields. At low fields, a quite homogeneous distribution of hysterons exists and at large field, a high concentration of hysterons at a field near to the antiferroelectric to ferroelectric phase transition can be seen. Moreover, when changing the delay between pulses of the PUND and the FORC measurements, we show that this weak ferroelectricity contribution is metastable and decreases with time.

Published
2023
Full Text
View/download PDF

5. Acoustic emission monitoring during gas permeation: a new operando diagnostic tool for porous membranes

Author

Etoungh D. Manga, Benoit Coasne, André Ayral, Martin Drobek, Philippe da Costa, Micka Bah, Hugues Blasco, Gilles Despaux, Emmanuel Le Clézio, Anne Julbe, Institut d’Electronique et des Systèmes (IES), Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Matériaux, MicroCapteurs et Acoustique (M2A), Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Institut Européen des membranes (IEM), Université Montpellier 2 - Sciences et Techniques (UM2)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM ICMMM), and Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut de Chimie du CNRS (INC)

Subjects
[SPI.ACOU]Engineering Sciences [physics]/Acoustics [physics.class-ph], Materials science, Filtration and Separation, Nanotechnology, Context (language use), [CHIM.MATE]Chemical Sciences/Material chemistry, 02 engineering and technology, Permeation, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Biochemistry, Signal, 0104 chemical sciences, Associated petroleum gas, Characterization (materials science), Membrane, Acoustic emission, Porous membrane, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], General Materials Science, Physical and Theoretical Chemistry, 0210 nano-technology, ComputingMilieux_MISCELLANEOUS
Abstract

In the area of membrane separations the development of powerful on-line diagnostic tools allowing the reliability insurance of both membranes and associated processes becomes a major concern. In this context, Acoustic Emission (AE) appears as a potentially attractive method to ensure i) quality control for membrane production lines and ii) on-line monitoring of their evolution when implemented in integrated industrial systems requiring high level of safety/security. In this work, simultaneous gas permeation measurements and acoustic emission technique have been coupled in order to characterize series of porous membranes operating under various conditions. AE events resulting from different gas transport mechanisms through porous membranes series have been identified and classified thanks to a statistical post-treatment of the recorded acoustic signals. A close relationship between AE signal characteristics, physicochemical properties of the porous membranes and associated gas transport mechanisms was established. These promising results constitute a key step in the development of an innovative tool for non-invasive on-line diagnosis dedicated to the characterization and control of porous ceramic membranes.

Published
2018
Full Text
View/download PDF

6. Composite microstructures and piezoelectric properties in tantalum substituted lead-free K0.5Na0.5Nb1-xTaxO3 ceramics

Author

Isabelle Monot-Laffez, Micka Bah, Mustapha Zaghrioui, Julien Bustillo, Florian Jean, Fabien Giovannelli, Frédéric Schoenstein, Pascal Marchet, Ecosystèmes forestiers (UR EFNO), Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), Laboratoire des Propriétés Mécaniques et Thermodynamiques des Matériaux (LPMTM), Université Paris 13 (UP13)-Institut Galilée-Centre National de la Recherche Scientifique (CNRS), GREMAN (matériaux, microélectronique, acoustique et nanotechnologies) (GREMAN - UMR 7347), Université de Tours-Institut National des Sciences Appliquées - Centre Val de Loire (INSA CVL), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), IRCER - Axe 3 : organisation structurale multiéchelle des matériaux (IRCER-AXE3), Institut de Recherche sur les CERamiques (IRCER), Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut National des Sciences Appliquées - Centre Val de Loire (INSA CVL), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Tours-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie du CNRS (INC)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut Galilée-Université Paris 13 (UP13), and Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Tours (UT)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, Scanning electron microscope, Niobium, Tantalum, Analytical chemistry, chemistry.chemical_element, Sintering, Spark plasma sintering, 02 engineering and technology, Composite ceramics, 01 natural sciences, 0103 physical sciences, Materials Chemistry, Ceramic, Ball mill, Spectroscopy, 010302 applied physics, Process Chemistry and Technology, Perovskites Tantalum, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, Microstructure, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, chemistry, visual_art, Ceramics and Composites, visual_art.visual_art_medium, Piezoelectric properties, 0210 nano-technology
Abstract

K 0.5 Na 0.5 Nb 1-x Ta x O 3 (KNNT) (with x = 0.00, 0.05, 0.10, 0.20, 0.30, 0.50 and 1) ceramics are prepared by ball milling and two calcinations at 830 °C for 5 h. Subsequent sintering of centimeter size pellets, 1–2 mm thick, is studied using conventional and spark plasma sintering techniques with various conditions. X-Ray diffraction and Raman spectroscopy phase identification reveal orthorhombic to tetragonal phase transitions occurring at about x = 0.50, associated to chemical disorder. Scanning electron microscope observations and associated energy dispersive X-ray spectroscopy analysis reveal some composite aspect of the ceramics. Substitution of niobium by tantalum, corresponding to x increase, decreases significantly the grain size but also the densification of the ceramics sintered by conventional sintering, while, enhancement of the piezoelectric properties is observed for both sintering techniques. Thanks to parameters optimization of the spark plasma sintering process, temperature-time-pressure, significant improvement of the relative density over 96%, is obtained for all the compositions sintered between 920 and 960 °C, under 50 MPa, for 5–10 min with heating rates of 100 °C/min. High relative permittivity (e r = 1027), piezoelectric charge coefficient (d 33 = 160 pC/N) and piezoelectric coupling factor (k p = 46%) are obtained in spark plasma sintered K 0.5 Na 0.5 Nb 1-x Ta x O 3 composite ceramics, for x ranging between 0.10 and 0.30 and for some specific spark plasma sintering conditions. Thus, tantalum single element substitution on niobium site, combined with spark plasma sintering, is revealed to be a powerful combination for the optimization and the reliability of piezoelectric properties in KNN system.

Published
2018
Full Text
View/download PDF

7. Ultrasonic transducers based on undoped lead-free (K0.5Na0.5)NbO3 ceramics

Author

Micka Bah, Frédéric Schoenstein, Lionel Haumesser, Jean-Robert Deschamps, Emmanuel Le Clézio, Frédéric Dorvaux, Isabelle Monot-Laffez, Christophe Brosseau, Fabien Giovannelli, GREMAN (matériaux, microélectronique, acoustique et nanotechnologies) (GREMAN - UMR 7347), Université de Tours-Institut National des Sciences Appliquées - Centre Val de Loire (INSA CVL), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Propriétés mécaniques et thermodynamiques des matériaux (PMTM), Centre National de la Recherche Scientifique (CNRS), Institut d’Electronique et des Systèmes (IES), Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Matériaux, MicroCapteurs et Acoustique (M2A), Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Institut National des Sciences Appliquées - Centre Val de Loire (INSA CVL), and Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Tours (UT)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, Acoustics and Ultrasonics, Relative permittivity, Spark plasma sintering, Sintering, Context (language use), Lead zirconate titanate, Piezoelectricity, [SPI.TRON]Engineering Sciences [physics]/Electronics, chemistry.chemical_compound, chemistry, visual_art, visual_art.visual_art_medium, Ultrasonic sensor, Ceramic, Composite material, ComputingMilieux_MISCELLANEOUS
Abstract

Lead zirconate titanate (PZT) ceramics are the dominant piezoelectric elements for non-destructive evaluation (NDE) and ultrasonic transducers devices. However, the presence of lead content may impose the scientific community to develop lead-free ceramics, concerning human health and environmental safety. During the past ten years, many contributions have highlighted the potential properties of complex compositions like LiNbO3, LiTaO3 and LiSbO3 in the lead-free (K0.5Na0.5)NbO3 KNN system. In this context, for the first time, the practical applications and the effectiveness of simply undoped (K0.5Na0.5)NbO3 (KNN) ceramics are investigated. KNN powder is prepared by conventional solid state mixed oxide route. Ceramics of this material are prepared using conventional sintering (CS) and spark plasma sintering (SPS). Thickness coupling factor k t of 44–46%, planar coupling factor k p of 29–45%, relative permittivity at constant strain e 33 , r S of 125–243 and acoustic impedance Z of 23–30 MRay are obtained for these two kinds of undoped KNN ceramics. Both ceramics are used to build single-element ultrasonic transducers. Relative bandwidth of 49–78% and insertion loss of −27 and −51 dB are obtained for SPS and CS transducers, respectively. These results are suitable for use in non-destructive evaluation. The effectiveness of undoped KNN is evaluated using the KLM model, and compared to standard PZT based probe. Finally, chemical aging test of undoped KNN has demonstrated its stability in water.

Published
2015
Full Text
View/download PDF

8. High electromechanical performance with spark plasma sintering of undoped K0.5Na0.5NbO3 ceramics

Author

Fabien Giovannelli, Emmanuel Le Clézio, Isabelle Monot-Laffez, Micka Bah, Guy Feuillard, Frédéric Schoenstein, GREMAN (matériaux, microélectronique, acoustique et nanotechnologies) (GREMAN - UMR 7347), Institut National des Sciences Appliquées - Centre Val de Loire (INSA CVL), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Tours (UT)-Centre National de la Recherche Scientifique (CNRS), Propriétés mécaniques et thermodynamiques des matériaux (PMTM), Centre National de la Recherche Scientifique (CNRS), Institut d’Electronique et des Systèmes (IES), Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Matériaux, MicroCapteurs et Acoustique (M2A), Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Université de Tours-Institut National des Sciences Appliquées - Centre Val de Loire (INSA CVL), and Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, Analytical chemistry, Spark plasma sintering, 02 engineering and technology, Dielectric, 01 natural sciences, 7. Clean energy, 0103 physical sciences, Materials Chemistry, Ceramic, Ball mill, ComputingMilieux_MISCELLANEOUS, 010302 applied physics, Process Chemistry and Technology, Atmospheric temperature range, 021001 nanoscience & nanotechnology, Microstructure, Grain size, [SPI.TRON]Engineering Sciences [physics]/Electronics, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Grain growth, visual_art, Ceramics and Composites, visual_art.visual_art_medium, 0210 nano-technology
Abstract

Lead free piezoelectric K 0.5 Na 0.5 NbO 3 (KNN) is synthesised by the conventional solid state mixed oxide route using dry ball milling. Spark plasma sintering technique (SPS) is an original and fast method which enables the grain growth to be controlled and allows to decrease a potential alkali volatilisation. Undoped KNN are sintered by SPS in the 920–975 °C temperature range, for dwell times of 5–15 min. The density range is 93–97%. Density, grain size and composition of samples are comparatively analysed. Electromechanical performances are measured and related to the microstructure. High planar coupling coefficient k p of 48%, thickness coupling factor k t of 45%, dielectric constant at constant strain e 33 S / e 0 of 328, and low mechanical losses δ m of 2% are reached for undoped KNN. These results are promising and suitable for transducer applications.

Published
2014
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results