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Silviu Cosmin Sandu

Cette personne n’est plus à l’EPFL

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Publications associées (45)

Fabrication of complex oxide microstructures by combinatorial chemical beam vapour deposition through stencil masks

Paul Muralt, Estelle Wagner, Giacomo Benvenuti, Silviu Cosmin Sandu, Andreea Veronica Savu, Scott Harada

Chemical Beam Vapour Deposition is a gas phase deposition technique, operated under high vacuum conditions, in which evaporated chemical precursors are thermally decomposed on heated substrates to form a film. In the particular equipment used in this work, ...

Elsevier2015

Thickness Dependence of Domain-Wall Patterns in BiFeO3 Thin Films

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

Unique properties of domain walls in ferroelectrics have been recently discovered but methods of their controlled engineering remain underdeveloped. Here we investigate the domain structure of Bi0.9La0.1FeO3 epitaxial thin films with piezoelectric force mi ...

Taylor & Francis2015

High Piezoelectric Longitudinal Coefficients in Sol-gel PZT Thin Film Multilayers

Paul Muralt, Silviu Cosmin Sandu, Alex Dommann, Nachiappan Chidambaram, Andrea Mazzalai, Antonia Neels, Davide Balma

A five-layer stack of lead zirconate titanate (PZT) thin films with Pt electrodes was fabricated for potential applications in nanoactuator systems. The 1 mu m thick PZT films were deposited by a sol-gel technique, the platinum electrodes by sputtering. Th ...

Wiley-Blackwell2014

Compliant ferroelastic domains in epitaxial Pb(Zr, Ti)O-3 thin films

Nava Setter, Silviu Cosmin Sandu, Ludwig Feigl

Ordered patterns of highly compliant ferroelastic domains have been created by use of tensile strained epitaxial Pb(Zr, Ti)O-3 thin films, of very low defect density, grown on DyScO3 substrates. The effect of 180 degrees switching on well-ordered a/c 90 de ...

Amer Inst Physics2014

Controlled stripes of ultrafine ferroelectric domains

Nava Setter, Alexander Tagantsev, Igor Stolichnov, Silviu Cosmin Sandu, Tomas Sluka, Mahamudu Mtebwa, Petr Yudin, Ludwig Feigl, Xiankui Wei, Konstantin Shapovalov

In the pursuit of ferroic-based (nano) electronics, it is essential to minutely control domain patterns and domain switching. The ability to control domain width, orientation and position is a prerequisite for circuitry based on fine domains. Here, we deve ...

Nature Publishing Group2014

Analysis of composition homogeneity and polarization orientation of PZT submicron fibers by micro-Raman spectroscopy

Nava Setter, Silviu Cosmin Sandu, Jin Wang

Micro-Raman spectroscopy is a convenient tool to probe individual objects with a feature size on the submicron scale. The phase, composition, and orientation of Pb(Zr,Ti)O-3 fibers fabricated via hydrothermal processing have been characterized by this tech ...

Elsevier Sci Ltd2014

Mechanism of hydrothermal growth of ferroelectric PZT nanowires

Nava Setter, Silviu Cosmin Sandu, Alexandre Durussel, Jin Wang, Mtabazi Geofrey Sahini

The formation mechanism of hydrothermally grown monocrystalline ferroelectric PZT nanowires is investigated. It is shown that the growth proceeds via a two-step process. Particles of the centrosymmetric PX-phase grow initially, having a fibrous morphology ...

2012

Experimental study of single triple-phase-boundary and platinum-yttria stabilized zirconia composite as cathodes for micro-solid oxide fuel cells

Paul Muralt, Janine Conde, Silviu Cosmin Sandu, Yan Yan

Micro-solid oxide fuel cell (mu SOFC) structures with annular Pt electrodes have been fabricated by means of silicon micromachining. The annular cathodes contained a defined triple phase boundary (TPB) length, which allowed the derivation of the ionic curr ...

2012

Electromechanical properties of Al0.9Sc0.1N thin films evaluated at 2.5 GHz film bulk acoustic resonators

Paul Muralt, Alvaro Artieda, Silviu Cosmin Sandu, Evgeny Milyutin, Ramin Matloub Aghdam

AlN films are employed in RF filters for wireless communication. We report on enhanced coupling factors k(t)(2) obtained by partial substitution of Al by Sc. Al0.88Sc0.12N films were deposited by reactive magnetron sputtering from an Al0.9Sc0.1 alloy targe ...

AIP American Institute of Physics2011

Properties of nanocomposite film combining hard TiN matrix with embedded fullerene-like WS2 nanoclusters

Silviu Cosmin Sandu

We have developed hard self-lubricant coatings combining a hard matrix (TiN) and a self-lubricant phase in the form of inorganic-like WS2 fullerene. The nanoparticles were injected from the preparation chamber directly to the sample surface during reactive ...

2011

Nanoporous YSZ film in electrolyte membrane of Micro-Solid Oxide Fuel Cell

Paul Muralt, Samuel Rey-Mermet, Silviu Cosmin Sandu, Yan Yan

Yttria stabilized zirconia (YSZ) with 8 mol% Y was deposited by reactive magnetron sputtering onto oxidized (100) silicon substrates. It was possible to switch film texture from (111) to (200) by applying a strong RF substrate bias. Transmission electron m ...

2010

A unique approach to reveal the nanocomposite nc-MN/SiN-layer architecture of thin films via electrical measurements

Rosendo Sanjines, Silviu Cosmin Sandu, Scott Harada

By addition of Si to a binary transition metal nitride MN (e.g. TiN, ZrN, NbN, CrN), the hardness, thermal stability and chemical inertness of films have been considerably improved. The formation of a ternary M–Si–N ternary phase is possible under specific ...

2010

Highly piezoelectric AlN thin films grown on amorphous, insulating substrate

Paul Muralt, Alvaro Artieda, Silviu Cosmin Sandu

AlN thin films were grown by reactive sputtering on amorphous SiO2 thin films. Film texture, x-ray rocking curve width, mechanical stress, and the clamped piezoelectric constant d33,f were studied as a function of rf bias power and substrate roughness. A h ...

2010

Combinatorial Discovery and Optimization of Amorphous HfO2-Nb2O5 Mixture with Improved Transparency

Paul Muralt, Patrik Willi Hoffmann, Estelle Wagner, Giacomo Benvenuti, Silviu Cosmin Sandu, Bamdad Afra, Ali Dabirian, Yury Kuzminykh, Scott Harada

Combinatorial high vacuum chemical vapor deposition (HV-CVD) of mixed HfO2-Nb2O5 thin films has been demonstrated to yield amorphous layers at substrate temperatures where individually deposited pure HfO2 and Nb2O5 films are polycrystalline. Spectroscopic ...

Electrochemical Society2010

Synchrotron X-ray diffraction study on a single nanowire of PX-phase lead titanate

Nava Setter, Silviu Cosmin Sandu, Jin Wang

Synchrotron X-ray diffraction (XRD) measurements of Pb-Ti-O fine acicular crystals (nanowires) of the so-called PX-phase have been performed. The theta-2 theta patterns of the nanowires dispersed on substrates with two different geometries indicated that t ...

2010

Influence of bias voltage on the microstructure and physical properties of magnetron sputtered Zr–Si–N nanocomposite thin films

Rosendo Sanjines, David Oezer, Silviu Cosmin Sandu

e report an investigation concerning the influence of ion bombardment on the nanostructure and physical properties of Zr–Si–N nanocomposite thin films. The films were deposited by reactive magnetron sputtering from individual Zr and Si targets. The Si cont ...

2009

Large-scale fabrication of titanium-rich perovskite PZT submicro/nano wires and their electromechanical properties

Nava Setter, Silviu Cosmin Sandu, Jian Wang

We report a 2-step approach to prepare tetragonal perovskite PbZr0.1Ti0.9O3 submicro/nano wires in gram scale and with over 95% wire content. Non-perovskite precursor wires were first fabricated by hydrothermal processing. A subsequent annealing in a PbO a ...

2009

Adhesion failures on hard coatings induced by interface anomalies

Silviu Cosmin Sandu

In this work, the lack of adhesion occurred during the up-scaling of the deposition of tribological coatings in a semi-industrial apparatus is interpreted. The adhesion problems were detected for both hard and self-lubricant coatings from W–Ti–N and W:C sy ...

2009

Self-Assembled Perovskite-Fluorite Oblique Nanostructures for Adaptive (Tunable) Electronics

Paul Muralt, Nava Setter, Alexander Tagantsev, Silviu Cosmin Sandu, Andreas Nöth, Maxim Gureev

The relative concentration of BaTiO3 and CeO2 is shown to control the inclination of composite growth. The oblique composite structures consist of tunable BaTiO3 nanofibers embedded in a CeO2 matrix, which lowers considerably the permittivity while signifi ...

Wiley2009

Precise control of multilayered structures of Nb–O–N thin films by the use of reactive gas pulsing process in DC magnetron sputtering

Silviu Cosmin Sandu

Multilayered niobium oxynitride films were deposited onto (100) Si using DC magnetron sputtering with a reactive gas pulsing process. The argon and nitrogen flows were kept constant during sputtering of a pure niobium target and the oxygen flow was pulsed ...

2008

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