Publications de Silviu Cosmin Sandu

Electrical transport properties of Ru1-xTixO2 films deposited by magnetron sputtering technique

The optical and electrical properties of Ru1-xTixO2 (0

PERGAMON-ELSEVIER SCIENCE LTD2021

Impact of negative bias on the piezoelectric properties through the incidence of abnormal oriented grains in Al0.62Sc0.38N thin films

Paul Muralt, Thomas La Grange, Silviu Cosmin Sandu, Mohammad Fazel Parsapour Kolour, Xiao Di, Robin Nigon, Lukas Riemer

Sputter deposited A1ScN films with an Sc content of 38 at % were investigated by X-ray diffraction and electron microscopy to study the influence of the radio frequency (RF) bias on the growth of abnormally oriented grains (AOG). Scanning electron microsco ...

2020

Low resistivity Ru1-xTixO2 thin films deposited by hybrid high-power impulse magnetron sputtering and direct current magnetron sputtering technique

Rosendo Sanjines, Alireza Karimi, Silviu Cosmin Sandu, Arnaud Magrez

The present paper reports on an experimental investigation of the structural, electrical and optical properties of Ru rich Ru1-xTixO2 thin films. Rutile single-phaseRu(1-x)Ti(x)O(2) thin films have been deposited by reactive hybrid High-power impulse magne ...

2019

Abnormal Grain Growth in AlScN Thin Films Induced by Complexion Formation at Crystallite Interfaces

Paul Muralt, Thomas La Grange, Silviu Cosmin Sandu, Stefan Mertin, Ramin Matloub Aghdam, Mohammad Fazel Parsapour Kolour, Vladimir Pashchenko

Sputter deposited Al(1-x)ScxN thin films with a Sc content from x = 0 to 43 at% are investigated by electron microscopy in order to study and explain the formation and growth of abnormally oriented grains (AOG). It is found that the latter did not nucleate ...

Wiley-VCH Verlag2019

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

Combinatorial study of low-refractive Mg-F-Si-O nano-composites deposited by magnetron co-sputtering from compound targets

Paul Muralt, Jean-Louis Scartezzini, Silviu Cosmin Sandu, Stefan Mertin

2018

Structural, tribo-mechanical, and thermal properties of NbAlN coatings with various Al contents deposited by DC reactive magnetron sputtering

Silviu Cosmin Sandu

DC reactive magnetron sputtered Nb2AlyNx coatings with various Al contents (y/(y + z)) ranging from 0 to 0.75 were deposited using different ratios of the currents applied to the Al and Nb targets in order to systematically control their chemical compositi ...

Elsevier Science Sa2017

Ex-situ AlN seed layer for (0001)-textured Al0.84Sc0.16N thin films grown on SiO2 substrates

Paul Muralt, Silviu Cosmin Sandu, Stefan Mertin, Mohammad Fazel Parsapour Kolour, Vladimir Pashchenko

It is more difficult to nucleate AlN-ScN alloy thin films (AlScN) in pure (0001)-texture than it is with pure AlN thin films. AlN thus can serve as seed layer for AlScN. Equipment limitations may lead to the problem of a vacuum break between AlN and AlScN ...

Ieee2017

Nanoscale Defect Engineering and the Resulting Effects on Domain Wall Dynamics in Ferroelectric Thin Films

Dragan Damjanovic, Nava Setter, Silviu Cosmin Sandu, Ludwig Feigl

Defect engineering is one of the cornerstones of the modern electronics industry. Almost all electronic devices include materials that have been doped by ion bombardment. For materials where crystallinity is essential, such as ferroelectrics, defect type a ...

Wiley-Blackwell2017

Enhanced piezoelectric properties of c-axis textured aluminium scandium nitride thin films with high scandium content: influence of intrinsic stress and sputtering parameters

Paul Muralt, Silviu Cosmin Sandu, Clemens Benedict Nyffeler, Gabriel Christmann, Stefan Mertin, Mohammad Fazel Parsapour Kolour, Vladimir Pashchenko

Aluminium scandium nitride (ASN) exhibits a largely enhanced piezoelectric response as compared to aluminium nitride (AlN), which makes it an upcoming piezoelectric material for use in next generation RF filters, sensors, actuators and energy harvesting de ...

Ieee2017

Key-features in processing and microstructure for achieving giant electrostriction in gadolinium doped ceria thin films

Paul Muralt, Silviu Cosmin Sandu, Mahmoud Hadad, Husnain Ashraf

Gadolinium doped ceria is a well-known oxygen ion conduction material for solid fuel cell electrolytes. With its centrosymmetric average lattice and relatively low bulk dielectric constant it does not look interesting for electromechanical applications. Ho ...

Elsevier2016

Internal electrical and strain fields influence on the electrical tunability of epitaxial Ba0.7Sr0.3TiO3 thin films

Nava Setter, Silviu Cosmin Sandu, Sarunas Bagdzevicius, Barbara Maraston Fraygola

Perpetual demand for higher transfer speed and ever increasing miniaturization of radio and microwave telecommunication devices demands new materials with high electrical tunability. We have investigated built in electrical and strain fields' influence on ...

Amer Inst Physics2016

Engineered a/c domain patterns in multilayer (110) epitaxial Pb(Zr,Ti)O-3 thin films: Impact on domain compliance and piezoelectric properties

Nava Setter, Silviu Cosmin Sandu, Mahamudu Mtebwa, Andrea Mazzalai, Arnaud Robert André Crassous

While there is extensive literature on the influence of both compressive and tensile strain on the domain patterns of (001) tetragonal ferroelectric thin films, little is known regarding domain engineering in (110) films. The primary reason is the absence ...

2016

A combinatorial chemical beam vapour deposition approach to tune the electrical conductivity of Nb:TiO2 films via Si co-doping

Paul Muralt, Estelle Wagner, Giacomo Benvenuti, Silviu Cosmin Sandu, Scott Harada, Marc Jobin

Chemical beam vapour deposition (CBVD) is a thin film deposition technique operated under high vacuum conditions in which film growth occurs through the thermally activated chemical decomposition of precursor molecules at the substrate surface. This techni ...

Elsevier Science Sa2016

Controlled creation and displacement of charged domain walls in ferroelectric thin films

Nava Setter, Silviu Cosmin Sandu, Tomas Sluka, Ludwig Feigl, Arnaud Robert André Crassous

Charged domain walls in ferroelectric materials are of high interest due to their potential use in nanoelectronic devices. While previous approaches have utilized complex scanning probe techniques or frustrative poling here we show the creation of charged ...

Nature Research2016

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

Nanocrystalline Low-Refractive Magnesium Fluoride Films Deposited by Reactive Magnetron Sputtering: Optical and Structural Properties

Paul Muralt, Jean-Louis Scartezzini, Silviu Cosmin Sandu, Stefan Mertin

In this work, we study MgF2 thin-film synthesis by reactive pulsed DC magnetron sputtering from a metallic magnesium target in a gas mixture of argon, oxygen, and carbon tetrafluoride (CF4). Nanocrystalline films on silicon and glass substrates with excell ...

Wiley-Blackwell2015

Negative-pressure-induced enhancement in a freestanding ferroelectric

Nava Setter, Alexander Tagantsev, Marco Cantoni, Brahim Dkhil, Silviu Cosmin Sandu, Jin Wang, Tomas Sluka, Alexander Kvasov, Xiankui Wei

Ferroelectrics are widespread in technology(1), being used in electronics and communications(2), medical diagnostics and industrial automation. However, extension of their operational temperature range and useful properties is desired(3-5). Recent developm ...

Nature Publishing Group2015

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

Post-deposition control of ferroelastic stripe domains and internal electric field by thermal treatment

Nava Setter, Silviu Cosmin Sandu, Monika Iwanowska, Ludwig Feigl

The dependence of the formation of ferroelastic stripe domain patterns on the thermal history is investigated by detailed piezoresponse force microscopy and X-ray diffraction experiments after and during annealing of tensile strained tetragonal Pb(Ti,Zr)O- ...

American Institute of Physics2015