Publications associées à Ferroelectric and piezoelectric properties of lanthanoid-substituted Bi4Ti3O12 thin films grown on (111)Pt and (100)IrO2 electrodes

Recent Advances in Piezoelectric Materials for Electromechanical Transducer Applications

Ferroelectricity has made a huge impact on science and technology since Joseph Valasek (then a Ph.D. student at the University of Minnesota) discovered it in 1920, a little longer than 100 years ago. Whereas Dr. Valasek's original research was motivated by ...

IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC2022

Field-induced ultrafast modulation of Rashba coupling at room temperature in ferroelectric alpha-GeTe(111)

Jan Hugo Dil

Rashba materials have appeared as an ideal playground for spin-to-charge conversion in prototype spintronics devices. Among them, alpha-GeTe(111) is a non-centrosymmetric ferroelectric semiconductor for which a strong spin-orbit interaction gives rise to g ...

Nature Portfolio2022

Ferroelectric Effects Probed by in situ Transmission Electron Microscopy

Reinis Ignatans

Ferroelectric perovskite oxides are widely used in sensors, actuators and optical modulators and, at the same time, they show promise for implementation in future applications such as energy storage, memory and cooling devices. At the infancy of the discov ...

EPFL2022

Induced giant piezoelectricity in centrosymmetric oxides

Dragan Damjanovic, Paul Muralt, Mahmoud Hadad, Vasiliki Tileli, Lukas Riemer, Daesung Park

Piezoelectrics are materials that linearly deform in response to an applied electric field. As a fundamental prerequisite, piezoelectric materials must have a noncentrosymmetric crystal structure. For more than a century, this has remained a major obstacle ...

American Association for the Advancement of Science2022

Stress effects on the impedance and ferroelectricity of PVDF-BiFeO3-MWCNT films using xanthan gum as dispersant

Frank Nüesch, Francis Owusu

Composite films based on dispersions of bismuth ferrite (BiFeO3) in polyvinylidene fluoride (PVDF) matrixes were prepared in the presence of multiwalled-carbon-nanotubes (MWCNT), using xanthan gum (XG) as dispersant. Films were prepared by spin coating and ...

ELSEVIER SCIENCE SA2022

Stretchable High Response Piezoelectric Elastomers Based on Polable Polynorbornene Fillers in a Polydimethylsiloxane Matrix

Frank Nüesch, Francis Owusu

To advance the field of piezoelectrics, it is desirable to find materials that combine high piezoelectricity with high elasticity. Applications such as self-sensors, stretchable electronics, soft robots, and energy harvesting would benefit tremendously. Ho ...

WILEY-V C H VERLAG GMBH2022

Stabilizing Unusual Oxidation States of Lanthanides in Molecular Complexes: Synthesis, Properties, and Reactivity

Aurélien René Willauer

The chemistry of divalent lanthanides has generated increasing interest in the past years due to their redox properties and unique reaction pathways. Notably, molecular complexes of low-valent lanthanides have been shown to be suitable one-electron reducta ...

EPFL2022

Piezoelectric suspended microchannel resonators

Damien Maillard

The objective of this PhD thesis is the development of a microfluidic platform for the real-time measurements of the mechanical properties of biological analytes at the single entity level. The systems developed for these purposes consist of piezoelectrica ...

EPFL2022

Actuation of piezoelectric structures with ferroelectric thin films having multiple elements

Paul Muralt

A method for driving piezoelectric elements of a micro-system. The piezoelectric elements comprising a ferroelectric thin film, and being configured to be part of any one or a combination of items of a list comprising: a cantilever, a bridge, a diaphragm, ...

2020

Functional and Responsive Polymers via Controlled Radical Polymerization

Jian Wang

This Thesis is built around 4 topics, which share in common that they all take advantage of the assets of controlled radical polymerization to either (i) prepare well-defined model systems to address fundamental research questions with regard to the sensit ...

EPFL2020

Dielectric Actuation Techniques at the Nanoscale: Piezoelectricity and Flexoelectricity

Kaitlin Marie Howell

Micro- and nanoelectromechanical systems (MEMS/NEMS) have long shown their potential to disrupt the established technologies. Over the past 15 years, MEMS have become fundamental components in filters, accelerometers, gyroscopes and gas sensors. MEMS are n ...

EPFL2019

Ferroelectric Self-Poling in GeTe Films and Crystals

Jan Hugo Dil

Ferroelectric materials are used in actuators or sensors because of their non-volatile macroscopic electric polarization. GeTe is the simplest known diatomic ferroelectric endowed with exceedingly complex physics related to its crystalline, amorphous, ther ...

2019

Growth, Integration, and Functional Characterization of AlScN Thin Films for RF MEMS Devices

Mohammad Fazel Parsapour Kolour

Mobile communication has grown explosively in recent years, leading to a strong demand for cheap, but high-performing bandpass filters with low insertion loss and smaller size. Surface acoustic wave (SAW) and thin film bulk acoustic wave (BAW) resonators r ...

EPFL2019

Material Parameter Extraction for Complex AlScN Thin Film Using Dual Mode Resonators in Combination with Advanced Microstructural Analysis and Finite Element Modeling

Paul Muralt, Thomas La Grange, Silviu Cosmin Sandu, Mohammad Fazel Parsapour Kolour, Vladimir Pashchenko, Kaoru Yamashita

Accurate property determination of the piezoelectric thin film material Al(1-x)Sc(x)N is necessary for designing the next generation of radio frequency resonators in mobile communication, and for testing results of ab initio calculations. Sound velocity an ...

WILEY2019

Fabrication and Characterisation of Epitaxial PMN-PT Nano-structures

Xiao Di

Downscaling of the minimal feature size, or the gate length has been the key for the exponential im-provement of the performance of the logic CMOS integrated circuits over the last six decades. How-ever, since about 2003, some fundamental limits in the dev ...

EPFL2019

Origin of Ferroelectric Phase in Undoped HfO2 Films Deposited by Sputtering

Igor Stolichnov, Matteo Cavalieri

Thin film metal-insulator-metal capacitors with undoped HfO2 as the insulator are fabricated by sputtering from ceramic targets and subsequently annealed. The influence of film thickness and annealing temperature is characterized by electrical and structur ...

WILEY2019

Effect of oxygen defects blocking barriers on gadolinium doped ceria (GDC) electro-chemo-mechanical properties

Paul Muralt, Robin Nigon, Ahsanul Kabir

Some oxygen defective metal oxides, such as cerium and bismuth oxides, have recently shown exceptional electrostrictive properties that are even superior to the best performing lead-based electrostrictors, e.g. lead-magnesium-niobates (PMN). Compared to pi ...

PERGAMON-ELSEVIER SCIENCE LTD2019

Design Considerations of Ferroelectric Properties for Negative Capacitance MOSFETs

Christian Enz, Mihai Adrian Ionescu, Farzan Jazaeri, Ali Saeidi

Impact of physical parameters of ferroelectric layer on the performance of Negative Capacitance (NC) MOSFETs is experimentally studied in this paper. Electrical behaviors of PZT-based and Si:HfO2-based NC-FETs are investigated and discussed. In a PZT-based ...

2018

Negative capacitance tunnel F£Ts: Experimental demonstration of outstanding simultaneous boosting of on-current, transconductance, overdrive, and swing

Igor Stolichnov, Mihai Adrian Ionescu, Farzan Jazaeri, Ali Saeidi

This paper demonstrates and experimentally reports the highest ever performance boosting in strained silicon-nanowire homojunction TFETs with negative capacitance, provided by matched PZT capacitors. Outstanding enhancements of I on , g m , and overdrive a ...

IEEE2018

Origins of the macroscopic symmetry breaking in centrosymmetric phases of perovskite oxides

Sina Hashemi Zadeh

Many perovskite materials experience a temperature-driven phase transition at the Curie temperature from a non-centrosymmetric polar ferroelectric phase to a paraelectric phase, where polarization is lost. The paraelectric phase is usually centrosymmetric ...

EPFL2017