Dielectric Properties Of Lead Potassium Lithium Niobate (Pb1,85K1,15Li0,15Nb5O15) With Tetragonal Tungsten Bronze (TTB) Type Structure

A new tungsten bronze ceramic oxide, Pb2-xK1+xLixNb5O15 (PKLN) (x =0.15) was prepared by high temperature solid-state reaction route. Structural and electrical properties are investigated using X-ray diffraction and dielectric measurements. Room temperature XRD pattern confirms the formation of the compound with an orthorhombic crystal system. The dielectric permittivity and the loss tangent of the sample have been measured in a frequency range 1Hz–1MHz and a temperature range 35–550 °C. Studies of dielectric properties show that the compound exhibits an anomaly at 425°C (usually called transition temperature).The electrical parameters of the material were studied using complex impedance spectroscopy showing that the compound exhibits non-Debye of relaxation process. In the paraelectric phase, activation energy was determined and the value is Eτ = 0.68 eV. The present ceramic is promising candidate for high dielectric constant and low loss dielectric ceramic.A new tungsten bronze ceramic oxide, Pb2-xK1+xLixNb5O15 (PKLN) (x =0.15) was prepared by high temperature solid-state reaction route. Structural and electrical properties are investigated using X-ray diffraction and dielectric measurements. Room temperature XRD pattern confirms the formation of the compound with an orthorhombic crystal system. The dielectric permittivity and the loss tangent of the sample have been measured in a frequency range 1Hz–1MHz and a temperature range 35–550 °C. Studies of dielectric properties show that the compound exhibits an anomaly at 425°C (usually called transition temperature).The electrical parameters of the material were studied using complex impedance spectroscopy showing that the compound exhibits non-Debye of relaxation process. In the paraelectric phase, activation energy was determined and the value is Eτ = 0.68 eV. The present ceramic is promising candidate for high dielectric constant and low loss dielectric ceramic

Influence of the dopants and of the microstructure on the ionic conductivity of zirconia

The electrical conductivity of monocristalline and polycristalline samples of yttria-doped zirconia was measured by impedance spectroscopy, in the temperature range 300-900°C and for oxygen partial pressures included between 10-24 and one atmosphere. Results show that the bulk conductivity is independent of the PO2 and varies with the amount of yttrium. The higher conductivities are obtained with zirconia samples doped with 9.5 moles %. According to recent literature oxygen diffusion data, the results have been analysed taking into account the participation of different kinds of defects to the transport processes. The grain boundary conductivity and the "composite effect" have been analysed taking into account microstructural characterizations. A maximum of ionic conductivity is observed with zirconia doped with 9.9 moles % yttrium when the amount of alumina is equal to approximatively 2 moles %

Structural and dielectric investigations of Pb(Zr0.2Ti0.8)O3 /SrTiO3 superlattices

International audienc

Towards negative capacitance in Pb(Zr0.2Ti0.8)O3 /SrTiO3 superlattices

International audienc

Structural and dielectric investigations of Pb(Zr0.2Ti0.8)O3 /SrTiO3 superlattices

International audienc

Towards negative capacitance in Pb(Zr0.2Ti0.8)O3 /SrTiO3 superlattices

International audienc

Pulsed laser deposition of PbMg1/3Nb2/3O3 thin films and PbMg1/3Nb2/3O3/PbTiO3 multilayers

We have fahricated epitaxial thin films of the relaxor Pb(Mg1/3Nb2/3)O3 (PMN) and multilayer structures of relaxor/ferroelectric Pb(Mg1/3Nb2/3)O3/PbTiO3 (PMN/PTO) using pulsed laser deposition. We present results obtained using reflection high energy electron diffraction (RHEED), x-ray diffraction (XRD) and transmission electron microscopy (TEM) on thin films of PMN grown on single crystal (100) SrTiO3 substrates using a stoichiometric PMN ceramic target and a PMN-2%Mg target. With the latter target we were able to produce pyrochlore free thin films. RHEED images 140Å PMN films consist of sharp lines and Kikuchi bands which indicate smooth surfaces. This is borne out by the observation of XRD Laue (thickness) oscillations. TEM images of PMN films with some pyrochlore show the PMN growth is columnar and the widths are on the order of 400Å. Multilayer structures of (PMNΛ/2 /PTOΛ/2)4 (Λ is the modulation period) were sucessfully grown. Satellite peaks were observed for these quadrilayer structures and preliminary analysis indicates that for the majority of the tetragonal PTO layers are oriented with the c-axis in the plane of the film