Posez n’importe quelle question sur les cours, conférences, exercices, recherches, actualités, etc. de l’EPFL ou essayez les exemples de questions ci-dessous.
AVERTISSEMENT : Le chatbot Graph n'est pas programmé pour fournir des réponses explicites ou catégoriques à vos questions. Il transforme plutôt vos questions en demandes API qui sont distribuées aux différents services informatiques officiellement administrés par l'EPFL. Son but est uniquement de collecter et de recommander des références pertinentes à des contenus que vous pouvez explorer pour vous aider à répondre à vos questions.
We investigate the non-linear dielectric properties of PbMg1/3Nb2/3O3 (PMN) single crystals and present the following experimental evidence: (a) the absence of the anomaly in the temperature dependence of non-linear coefficients in the relationship between ...
Direct evidence for freezing in two relaxer ferroelectrics, PbMg1/3Nb2/3O3 and PbSc1/2Ta1/2O3, at a certain temperature T-f not equal 0K was obtained from the temperature dependence of the maximum relaxation time, tau(max), It was shown that tau(max)(T) fo ...
A phenomenological thermodynamic theory of ferroelectric thin films epitaxially grown on cubic substrates is developed using a new form of the Gibbs function, which corresponds to the actual mechanical boundary conditions of the problem. It is found that t ...
Brillouin scattering from transverse-acoustic modes of SrTiO3 is observed, while the frequencies of the soft polar modes are remeasured with hyper-Raman scattering. It is shown that an anomalous decrease of sound velocities at low temperatures results from ...
A comprehensive study of: leakage conduction in Pb(ZrxTi1-x)O-3 films with Pt electrodes is carried out. The conduction properties of films prepared in different ways (sol-gel coating, metalorganic chemical vapor deposition, sputtering) were studied by usi ...
The fatigued state of Pt-PZT-Pt ferroelectric capacitors (FECAP) was investigated by means of piezoelectric coefficient, polarisation charge and permittivity measurements. The suppression of switching polarisation P-r(s) appears to be the result of freezin ...
The scenarios of the size effects which may account for the difference in the switching properties of ferroelectric thin films and bulk ferroelectrics are critically reviewed. It is shown that the two often used models (the Janovec-Kay-Dunn surface nucleat ...
Piezoelectric and dielectric aging was studied in Pb(Zr,Ti)O-3 (PZT) thin films and bulk ceramics. It was found that piezoelectric aging in thin films obeys the logarithmic time dependence with the relative aging rate much higher than that of the dielectri ...
The effects of niobium doping on the hysteresis parameters of sol-gel Pb-1.1-x/2(Zr0.53Ti0.47)(1-x)NbxO3 (0 < x < 0.05) have been reported fbr two sets of films with analogous grain size and degree of (111) texture but with different surface microstructure ...
Dielectric permittivity of PbMg1/3Nb2/3O3 (PMN) relaxor was investigated as a function of DC bias and AC driving field. In single crystals, DC and AC field effects exhibited very different behavior, including anisotropy and sign of the effect. It was shown ...
