Search results for "Biasing"
showing 10 items of 69 documents
Dependence of dielectric permittivity on bias field in Pb1−xBaxSc0.5Nb0.5O3
2001
Abstract Bias field effect on the dielectric permittivity is studied in Badoped lead scandium niobate ferroelectric ceramics (PBSN-x) prepared by conventional technology. Results of this work allow to analyse the mechanism of possible formation and motion of domain and/or phase boundaries in the explored ferroelectric ceramics.
Bias Field Effect on Dielectric Response in the Region of Phase Transitions in (Pb,La)(Zr,Sn,Ti)O3Ceramics
2007
The dielectric response of (Pb 0.97 La 0.02 ) (Zr 0.53 Ti 0.12 Sn 0.35 )O 3 (PLZTS-2/53/12/35) ceramics was measured as a function of DC bias field E =. As the bias field intensity increases the values of ϵ′ max and ϵ” max are found to shift towards a lower temperature. A possible coexistence of the ferroelectric and antiferroelectric phases over a wide range of temperatures in the PLZTS-2/53/12/35 samples is assumed to explain the observed features of ϵ′ (T), ϵ” (T), and ϵ′ (E=) curves.
Temperature and electric field dependence of the permittivity of Ba0.9Sr0.1TiO3 films epitaxially grown on cuprate electrodes
1999
Abstract Cuprate, high-temperature superconductors and perovskite ferroelectrics have similar crystal structures and chemical constituents and, therefore, it can be advantageous to deposit epitaxial trilayer capacitors with high-Tc electrodes and operate these at room temperature, well above the transition temperature Tc, in order to achieve a high dielectric constant, tunability, and relatively low microwave loss. Epitaxial heterostructures (200 nm)YBa2Cu3O7−δ/(600 nm)Ba0.9Sr0.1TiO3/(200 nm)YBa2Cu3O7−δ and (200 nm)NdBa2Cu3O7−δ/(600 nm)Ba0.9Sr0.1TiO3/(200 nm)NdBa2Cu3O7−δ were laser deposited on (100)LaAlO3 substrates. The relative dielectric permittivity e/e0 of Ba0.9Sr0.1TiO3 was in the ra…
Photoelectrochemical investigation of passive layers formed on Fe in different electrolytic solutions
2004
Abstract The passive films formed on Fe in different electrolytic solutions, spanning almost the overall pH range, and with different growth procedures were investigated systematically by photocurrent spectroscopy. The potentiodynamic growth curves are compared both in aerated and de-aerated electrolytes and a potentiostatic growth procedure is also employed. For high positive formation potentials, similar anodic spectra are recorded in all solutions giving an optical gap very close to that expected for crystalline Fe2O3. The origin of photocurrent spikes is also investigated and the effect of the formation potential upon the measured absorption threshold is discussed taking into account th…
Experimental investigation of the breakdown of the Onsager-Casimir relations
2006
We use magnetoconductance fluctuation measurements of phase-coherent semiconductor billiards to quantify the contributions to the nonlinear electric conductance that are asymmetric under reversal of magnetic field. We experimentally determine that the average asymmetric contribution is linear in magnetic field (for magnetic flux much larger than one flux quantum) and that its magnitude depends on billiard geometry. In addition, we find an unexpected asymmetry in the power spectrum characteristics of the magnetoconductance with respect to reversal of magnetic field and bias voltage.
Isotropic-nematic interfacial tension of hard and soft rods: Application of advanced grand canonical biased-sampling techniques
2005
Coexistence between the isotropic and the nematic phase in suspensions of rods is studied using grand canonical Monte Carlo simulations with a bias on the nematic order parameter. The biasing scheme makes it possible to estimate the interfacial tension gamma in systems of hard and soft rods. For hard rods with L/D=15, we obtain gamma ~ 1.4 kB T/L^2, with L the rod length, D the rod diameter, T the temperature, and kB the Boltzmann constant. This estimate is in good agreement with theoretical predictions, and the order of magnitude is consistent with experiments.
Image charge dynamics in time-dependent quantum transport
2012
In this work we investigate the effects of the electron-electron interaction between a molecular junction and the metallic leads in time-dependent quantum transport. We employ the recently developed embedded Kadanoff-Baym method [Phys. Rev. B 80, 115107 (2009)] and show that the molecule-lead interaction changes substantially the transient and steady-state transport properties. We first show that the mean-field Hartree-Fock (HF) approximation does not capture the polarization effects responsible for the renormalization of the molecular levels neither in nor out of equilibrium. Furthermore, due to the time-local nature of the HF self-energy there exists a region in parameter space for which …
Arrays of normal metal tunnel junctions in weak Coulomb blockade regime
1995
Universal features of I–V characteristics of one‐dimensional arrays of normal metal tunnel junctions have been tested against inhomogenities in the junction parameters, number of junctions in the array, and magnetic field. We find that the differential conductance versus bias voltage obeys the analytic form to within 1% if the fabrication errors are smaller than 10% in junction areas, and if the array has more than ten junctions. Furthermore, the universal relation is insensitive to magnetic field at least up to 8 T.
Real-time switching between multiple steady-states in quantum transport
2010
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Solid State Analogue of a Double Slit Interferometer
2002
In a conventional optical double slit interferometer Fig. 1a light emerges from a source at a point O’, passes through two slits A and B and forms an interference pattern at a point O. If the source provides monochromatic radiation the coherence between optical paths O’AO and O’BO is preserved at all reasonable scales. The intensity of the interference pattern at a given point O can be altered by changing the distance ∣O’AO∣ - ∣O’BO∣.