Publications associées à Domain walls and defects in ferroelectric materials

Instabilities in Elastic and Magneto-Elastic Beams and Shells: from Shell Buckling to the Design of a Programmable Braille Reader

In this thesis, we conduct a comprehensive investigation into structural instabilities of both elastic and magneto-elastic beams and shells, resulting in a creative proposal to design a programmable braille reader. Methodologically, we combine numerical si ...

EPFL2024

Nonlinear electro-mechanical coupling and thermally stimulated currents in relaxor ferroelectrics

Lukas Riemer

In this work, the emergence of polarization and electro-mechanical coupling in Pb(Mg1/3Nb2/3)O3 and Pb(Mg1/3Nb2/3)O3 â PbTiO3 was investigated by means of thermally stimulated current, and nonlinear dielectric and electro-mechanical measurements. The pre ...

EPFL2022

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

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

Giant switchable non thermally-activated conduction in 180 degrees domain walls in tetragonal Pb(Zr,Ti)O-3

Igor Stolichnov, Mihai Adrian Ionescu, Felix Risch

Conductive domain walls in ferroelectrics offer a promising concept of nanoelectronic circuits with 2D domain-wall channels playing roles of memristors or synoptic interconnections. However, domain wall conduction remains challenging to control and pA-rang ...

Nature Portfolio2022

Defect-induced magnetism in homoepitaxial SrTiO3

Mihai Adrian Ionescu, Daesung Park

Along with recent advancements in thin-film technologies, the engineering of complex transition metal oxide heterostructures offers the possibility of creating novel and tunable multifunctionalities. A representative complex oxide is the perovskite stronti ...

AIP Publishing2022

PUS3-related disorder: Report of a novel patient and delineation of the phenotypic spectrum

Alessandro Borghesi

PUS3 encodes the pseudouridylate synthase 3, an enzyme catalyzing the formation of tRNA pseudouridine, which plays a critical role in tRNA structure, function, and stability. Biallelic pathogenic variants of PUS3 have been previously associated with severe ...

WILEY2022

Challenges and Applications to Operando and In Situ TEM Imaging and Spectroscopic Capabilities in a Cryogenic Temperature Range

Martial Duchamp, Vasiliki Tileli, Reinis Ignatans

In this Account, we describe the challenges and promising applications of transmission electron microscopy (TEM) imaging and spectroscopy at cryogenic temperatures. Our work focuses on two areas of application: the delay of electron-beam-induced degradatio ...

AMER CHEMICAL SOC2021

Defect engineered nanostructured LaFeO3 photoanodes for improved activity in solar water oxidation

Mounir Driss Mensi, Kevin Sivula, Xavier Pereira Da Costa, Nestor Guijarro Carratala, Liang Yao, Yongpeng Liu

LaFeO3 (LFO) is recognized as a candidate material for solar water oxidation, but its photoelectrochemical response remains modest and stagnant. With the aim of advancing LFO photoanodes for the oxygen evolution reaction (OER), here, a nanorod array-type e ...

Royal Society of Chemistry2021

Individual Barkhausen Pulses of Ferroelastic Nanodomains

Dragan Damjanovic, Vasiliki Tileli, Reinis Ignatans

Ferroelectric materials, upon electric field biasing, display polarization discontinuities known as Barkhausen jumps, a subclass of a more general phenomenon known as crackling noise. Herein, we follow at the nanoscale the motion of 90 degree needle domain ...

2021

Interface-Dominated Time-Dependent Behavior of Poled Poly(Vinylidene Fluoride–Trifluoroethylene)/Barium Titanate Composites

Dragan Damjanovic, Yves Leterrier, Véronique Michaud, Sara Dalle Vacche

Composites in which particles of ferroelectric ceramic phase are randomly dispersed in a polymeric matrix are of interest because of flexibility, conformability, and ease of processing. However, their piezoelectric properties are rather low, unless very hi ...

2020

Finite-size corrections of defect energy levels involving ionic polarization

Alfredo Pasquarello, Julia Anna Wiktor, Stefano Falletta

We develop a scheme for finite-size corrections of vertical transition energies and single-particle energy levels involving defect states with built-in ionic polarization in supercell calculations. The method accounts on an equal footing for the screening ...

2020

Corrections to “Experimental Details of a Steep-Slope Ferroelectric InGaAs Tunnel-FET With High-Quality PZT and Modeling Insights in the Transient Polarization”

Igor Stolichnov, Mihai Adrian Ionescu, Ali Saeidi, Hiroshi Iwai

This correspondence highlights that the Gibbs free energy description of a ferroelectric capacitor in series with a paraelectric capacitor, depends on the initial charge on the plates of the ferroelectric capacitor. An incomplete Gibbs free energy descript ...

2020

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

GaAs nanoscale membranes: prospects for seamless integration of III-Vs on silicon

Anna Fontcuberta i Morral, Gözde Tütüncüoglu, Martin George Friedl, Luca Francaviglia, Nicholas Paul Morgan, Andres Maria Raya Bejarano, Sara Marti Sanchez, Vladimir Dubrovskii

The growth of compound semiconductors on silicon has been widely sought after for decades, but reliable methods for defect-free combination of these materials have remained elusive. Recently, interconnected GaAs nanoscale membranes have been used as templa ...

2020

Improving delamination resistance through tailored defects

John Botsis

Delamination is a well-known damage mode exhibited by laminated composites which has been extensively studied in unidirectional laminates (UD). In this work, a novel strategy consisting of the introduction of a small interlaminar defect to enhance the frac ...

2020

Identifying and Tracking Defects in Dynamic Supramolecular Polymers

Michele Ceriotti, Piero Gasparotto

A central paradigm of self-assembly is to create ordered structures starting from molecular monomers that spontaneously recognize and interact with each other via noncovalent interactions. In recent years, great efforts have been directed toward perfecting ...

AMER CHEMICAL SOC2020

Optoelectronic and magnetic properties induced by atomic defects in two-dimensional semiconductors

Alessio Scavuzzo

Two-dimensional (2D) materials have attracted increasing attention over the last decade owing to their remarkable mechanical, electrical and optical properties. Following the groundbreaking discovery of graphene, a plethora of other atomically-thin materia ...

EPFL2020

Field-induced reorientation of helimagnetic order in Cu2OSeO3 probed by magnetic force microscopy

Helmuth Berger

Cu2OSeO3 is an insulating skyrmion-host material with a magnetoelectric coupling giving rise to an electric polarization with a characteristic dependence on the magnetic-field (H) over right arrow. We report a magnetic force microscopy imaging of the helic ...

AMER PHYSICAL SOC2020

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