Publications associées à Pressure-induced piezoelectric effects in near-lattice-matched GaN/AlInN quantum wells

Al0.83Sc0.17N Contour-Mode Resonators With Electromechanical Coupling in Excess of 4.5%

Paul Muralt, Luis Guillermo Villanueva Torrijo, Andrea Lozzi

In this paper, we demonstrate the fabrication of contour-mode resonators (CMRs) with Al0.83Sc0.17N as a piezoelectric layer. Moreover, we assess the electromechanical coupling and the maximum achieved quality factor from 150 to 500 MHz. In comparison to pu ...

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

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

Strain generation and energy-conversion mechanisms in lead-based and lead-free piezoceramics

Dragan Damjanovic

Piezoelectric ceramics generate strain through the intrinsic piezoelectric effect, the motion of ferroelectric domain walls, or through field-induced phase transitions. The enhanced piezoelectric properties observed in morphotropic solid solutions arise fr ...

2018

A new bioinspired method for pressure and flow sensing based on the underwater air-retaining surface of the backswimmer Notonecta

Goran Lovric

In technical systems, static pressure and pressure changes are usually measured with piezoelectric materials or solid membranes. In this paper, we suggest a new biomimetic principle based on thin air layers that can be used to measure underwater pressure c ...

2018

Guest dynamics in methane hydrates and hydrogen hydrates under high pressure

Umbertoluca Ranieri

Hydrates of gas are non-stoichiometric inclusion compounds constituted of water and gas. Therein, the water molecules are hydrogen-bonded and form three-dimensional crystalline networks incorporating different kinds of polar or nonpolar guest gas molecules ...

EPFL2018

A concept of wireless and passive very-high temperature sensor

Paul Muralt, Ramin Matloub Aghdam, Andrea Mazzalai

There is a need for sensors capable operating at temperatures above 1000 degrees C. We describe an innovative sensor that might achieve this goal. The sensor comprises two main elements: a thermocouple and a surface acoustic wave (SAW) strain sensor. The c ...

Amer Inst Physics2017

Pressure-dependent elastic and transport properties of porous and permeable rocks: Microstructural control

Christian David, Lucas Xan Pimienta

Although several studies aimed at linking electrical and hydraulic transport properties in rocks, the existing models remain at most incomplete. Based on this observation, in addition to the transport properties, this contribution investigates the pressure ...

Amer Geophysical Union2017

From 2D to 3D Characterization of Materials Subjected to Extreme Pressure and Temperature Conditions

Farhang Nabiei

Planetesimal were the first planetary objects to form in the solar system, which later grew to make the proto-planets. Most of these bodies were differentiated as a result of internal heating. Several differentiated bodies have, then, been accreted followi ...

EPFL2017

Piezoelectric Coefficients of AlScN Thin Films in Comparison

Paul Muralt, Ramin Matloub Aghdam, Mahmoud Hadad

Since the discovery of a high piezoelectric response in AlScN by Akiyama and coworkers in 2009, a number of works of other groups confirmed the large increase of piezoelectricity when partially substituting Al cations by Sc cations, as long as the alloy gr ...

Ieee2016

Piezoelectric response of BiFeO3 ceramics at elevated temperatures

Dragan Damjanovic

The high Curie temperature (T-C similar to 825 degrees C) of BiFeO3 has made this material potentially attractive for the development of high-T-C piezoelectric ceramics. Despite significant advances in the search of new BiFeO3-based compositions, the piezo ...

AIP American Institute of Physics2016

Piezoelectric enhancement under negative pressure

Nava Setter, Alexander Tagantsev, Silviu Cosmin Sandu, Jin Wang, Tomas Sluka, Alexander Kvasov

Enhancement of ferroelectric properties, both spontaneous polarization and Curie temperature under negative pressure had been predicted in the past from first principles and recently confirmed experimentally. In contrast, piezoelectric properties are expec ...

Nature Publishing Group2016

Converse mode piezoelectric coefficient for lead zirconate titanate thin film with interdigitated electrode

Paul Muralt, Silviu Cosmin Sandu, Nachiappan Chidambaram, Ramin Matloub Aghdam, Andrea Mazzalai, Robin Nigon, Davide Balma

The use of interdigitated electrodes (IDEs) in conjunction with ferroelectric thin films shows many attractive features for piezoelectric MEMS applications. In this work, growth of {1 0 0}-textured lead zirconate titanate (PZT) thin films was achieved on i ...

Institute of Physics2015

Characterization and Fatigue of the Converse Piezoelectric Effect in PZT Films for MEMS Applications

Paul Muralt, Nachiappan Chidambaram, Ramin Matloub Aghdam, Andrea Mazzalai, Davide Balma

A measurement setup for the detailed study of the transverse piezoelectric coefficient e(31,f) in the converse (actuator) mode was developed. It allows the assessment of the piezoelectric stress in thin films on silicon cantilevers and provides for a corre ...

Institute of Electrical and Electronics Engineers2015

Hydroacoustic Modeling of a Cavitation Vortex Rope for a Francis Turbine

Christian Landry

Hydraulic machines subject to off-design operation involve the presence of cavitating flow regimes in the draft tube. The cavitation vortex rope at part load conditions is described as an excitation source for the hydraulic system, and interactions between ...

EPFL2015

The strength of ruby from X-ray diffraction under non-hydrostatic compression to 68 GPa

Susannah McGregor Dorfman

Polycrystalline ruby (alpha-Al2O3:Cr3+), a widely used pressure calibrant in high-pressure experiments, was compressed to 68.1 GPa at room temperature under non-hydrostatic conditions in a diamond anvil cell. Angle-dispersive X-ray diffraction experiments ...

Springer2014

Pressure effect on magnetism and multiferroicity in Mn2GeO4

Jonathan White

The effect of high pressure exceeding 6 GPa on magnetism and multiferroicity was investigated for the olivine Mn2GeO4 that shows successive magnetic transitions at ambient pressure and a ferroelectric ground state driven by spin- spiral order. We measured ...

Amer Physical Soc2014

Magnetic, structural, and electronic properties of the multiferroic compound FeTe2O5Br with geometrical frustration

Helmuth Berger

We report electron spin resonance (ESR), Raman scattering, and interband absorption measurements of the multiferroic FeTe2O5Br with two successive magnetic transitions at T-N1 = 11.0 K and T-N2 = 10.5 K. ESR measurements show all characteristics of a low-d ...

Iop Publishing Ltd2014

Equation of state of liquid mercury to 520 K and 7 GPa from acoustic velocity measurements

Livia Eleonora Bove Kado

Ultrafast acoustics measurements on liquid mercury have been performed at high pressure and temperature in a diamond anvil cell using picosecond acoustic interferometry. We extract the density of mercury from adiabatic sound velocities using a numerical it ...

American Institute of Physics2014

An in situ diffraction study of domain wall motion contributions to the frequency dispersion of the piezoelectric coefficient in lead zirconate titanate

Dragan Damjanovic

The contribution of non-180 degrees domain wall displacement to the frequency dependence of the longitudinal piezoelectric coefficient has been determined experimentally in lead zirconate titanate using time-resolved, in situ neutron diffraction. Under sub ...

American Institute of Physics2013