Publications by Nava Setter | EPFL Graph Search

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Mechanisms of polarization switching and fatigue in (Pb, La)(Zr, Ti)O-3 (PLZT) films are studied by comparative analysis of degradation and leakage conduction of PLZT capacitors with Pt, SrRuO3 (SRO), and layered Pt/SRO (80/5 nm) electrodes. It is found that the asymmetrical Pt/SRO/PLZT/Pt structure exhibits a good fatigue performance in combination with low leakage like that on identically processed Pt/PLZT/Pt capacitor. This asymmetrical structure exhibits very unusual dependence of the endurance of switc

Strain engineering is a widespread strategy used to enhance performance of devices based on semiconductor thin films. In ferroelectrics strain engineering is used to control the domain pattern: When an epitaxial film is biaxially compressed, e.g. due to la ...

The internal structure of neutral 180 degrees domain walls in perovskite-type ferroelectrics is studied in terms of Landau theory taking into account electromechanical coupling. The study is focused on the wall bistability, a factor of potential interest f ...

The properties of interstitial and substitutional Li in wurtzite ZnO are modeled using hybrid density functional calculations. We investigate the impact of the band-gap error on the formation energies of the two defects and their dependence on the Fermi le ...

The influence of the uniaxial bias stress on the piezoelectric properties of tetragonal BaTiO3 and PbTiO3 monodomain crystals is modeled in the framework of the phenomenological Landau-Ginzburg-Devonshire theory. It is shown that tensile and compressive st ...

Using pulsed-laser deposition, a two-step growth technique was applied to epitaxial SrTiO3 (STO) thin films on LaAlO3 substrates providing a way to obtain an effective strain relaxation in these films otherwise strained due to lattice mismatch between film ...

Hetero interfaces between metal-oxides display pronounced phenomena such as semiconductor-metal transitions, magnetoresistance, the quantum hall effect and superconductivity. Similar effects at compositionally homogeneous interfaces including ferroic domai ...

We studied polarization switching of 295 nm thick -oriented-Pb(Zr0.45Ti0.55)O-3 (PZT) thin-film capacitors through a polarization hysteresis loop and piezoelectric force microscopy (PFM) on top of the Pt electrode. Positive voltage pulses of 450 kV/cm and 2.5 ms were applied to the top as a poling pulse. Negative pulses ranging from -45 to -60 kV/cm at an interval of 3 kV/cm were applied to the top electrode. After each pulse, we performed PFM imaging by applying 17 kHz ac voltage of 1 V peak to peak t

A theoretical model for the dc bias dependence of induced acoustic resonances in paraelectric materials is presented. The field dependent piezoelectric constitutive equations were derived from the Landau free energy expansion with respect to the ferroelect ...

We present a simple approach enabling analytical treatments of size effects in ferroelectric samples of complicated shapes for the cases where long-range depolarizing effects are not involved. The key element of the approach is the presentation of the ener ...

Strontium barium niobate thin films have been deposited by pulsed laser deposition on (111)-textured Pt films, p-doped Si(I 00) and Nb doped STO (SrTiO3) single crystals. The deposition parameters were optimized for obtaining phase pure (001)-oriented films from stochiometric targets. The samples were annealed in oxygen to improve top electrode adhesion and reduce oxygen vacancies. The SBN/substrate interfaces were investigated by means of TEM combined with EDAX chemical analysis. Growth on silicon resulted

The persistent field effect control of ferromagnetism in a diluted magnetic semiconductor by low-voltage polarizing pulses is demonstrated in a ferroelectric gate field effect transistor configuration. The Curie temperature of the (Ga,Mn)As channel is unam ...

The preparation and dielectric properties of potassium niobate tantalate (KTN) have been investigated with the aim of exploring the material's potential for ferroelectric tunable applications. The samples were prepared both by conventional sintering in air ...

Transparent single crystals of the perovskite Pb(Zn-1/3,Nb-2/3)O-3-PbTiO3 (PZN-PT) were grown from different lead fluxes in sealed platinum crucibles. A temperature gradient furnace was used (temperature gradient on crucible: 30-50 degreesC). Optimization of growth temperature range and cooling rates was carried out in fluxes of PbO, Pb3O4 with and without an addition of B2O3. The growth nature range was typically 1150 degreesC --> 930 degreesC (on crucible top) with cooling rates of 0.8 - 1 degreesC/h for

Sol-gel processing parameters of Pb0.99Zr0.55Sn0.37Ti0.06Nb0.02O3 thin films were studied. Effects of H2O, HNO3 and formamide additives on solution gelation and film properties were investigated. Thin films were prepared on Ti/Pt and Ta/Pt metallized Si substrates. Film microstructures were characterized using SEM, TEM/EDS and XPS. Film microstructures typically contained 'rosette' structures. Strain response of the films under applied electric fields was measured using a double beam interferometer. A piezo

The concept of a field-effect transistor with ferroelectric gate has been implemented using the GaN/AlGaN heterostructure combined with Pb(Zr,Ti)O-3 ferroelectric layer. The processing conditions were optimized in a way to obtain textured Pb(Zr,Ti)O-3 film ...

The dependence of the permittivity, on uniaxial pressure of ceramics in the paraelectric, ferroelectric and relaxer phases has been investigated for BaTiO3, Pb(ZrTi)O-3 and Pb(Mg1/3Nb2/3)O-3. In the paraelectric ic phase, upon the application of stress, a reversible decrease in the permittivity is observed. In the ferroelectric phase, the observed behaviors can be divided in two classes depending on the type of ionic defects present in the ceramics. Both behaviors are characterized by an instantaneous incre

Ferroelectric nanostructures have recently attracted much attention due to the quest of miniaturizing devices and discovering novel phenomena. In particular, studies conducted on two-dimensional and zero-dimensional ferroelectrics have revealed original pr ...

Electroceramics research is driven by technology and device applications. This growing field includes a vast number of magnetic, dielectric, ionically conducting, semiconducting, and superconducting ceramics used in domains as diverse as transportation, industrial production, power engineering, medicine and health care, consumer electronics, and communication. Al the turn of the decade, three major trends are gaining importance: Materials integration issues play an increasingly important role driven by the

Interest in PVDF-TrFE copolymers as ferroelectric material for Memory application is driven by the prospect of having low cost, low operating voltage and fully organic device. Some previous studies reported FET designs using copolymers [refs 1,2] but none ...

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Top-interface-controlled switching and fatigue endurance of (Pb, La)(Zr,Ti)O-3 ferroelectric capacitors

Charge screening strategy for domain pattern control in nano-scale ferroelectric systems

Bistability of ferroelectric domain walls: Morphotropic boundary and strain effects

A hybrid density functional study of lithium in ZnO: Stability, ionization levels, and diffusion

Enhancement of the piezoelectric response of tetragonal perovskite single crystals by uniaxial stress applied along the polar axis: A free-energy approach

Strain relaxation of epitaxial SrTiO3 thin films on LaAlO3 by two-step growth technique

Free-electron gas at charged domain walls in insulating BaTiO3

Evidence for forward domain growth being rate-limiting step in polarization switching in < 111 >-oriented-Pb(Zr0.45Ti0.55)O-3 thin-film capacitors

Electrical tuning of dc bias induced acoustic resonances in paraelectric thin films

Effective-surface-energy approach for size effects in ferroics

Microstructural and electrical properties of (Sr,Ba)Nb2O6 thin films grown by pulsed laser deposition

Toward a low-voltage multiferroic transistor: Magnetic (Ga,Mn)As under ferroelectric control

Synthesis and dielectric characterization of potassium niobate tantalate ceramics

Flux growth and characterization of quasi cubic PZN-PT single crystals

Sol-gel processing of PNZST thin films on Ti/Pt and Ta/Pt metallizations

Ferroelectric gate for control of transport properties of two-dimensional electron gas at AlGaN/GaN heterostructures

Uniaxial stress dependence of the permittivity of electroceramics

Low-Symmetry Phases in Ferroelectric Nanowires

Electroceramic materials

1T Memory Cell Based on PVDF-TrFE Field Effect Transistor