Climate change has been linked with the establishment and geographical expansion of zoonotic diseases, an example of which is the well-documented increase in human cases of Lyme disease in Quebec, Canada. As temperatures continue to increase in Quebec, it is anticipated that several zoonotic diseases will be affected. In response to the growing zoonotic issues facing public health authorities, Quebec's Multi-Party Observatory on Zoonoses and Adaptation to Climate Change (Observatoire multipartite québécois sur les zoonoses et l'adaptation aux changements climatiques) (the Observatory) was founded in 2015 as part of the Quebec government's Climate Change Action Plan (Plan d'action 2013-2020 sur les changements climatiques). The Observatory was designed to bring together agencies involved in formulating public policy and experts from the disciplines of human health, animal health and environmental sciences, in a manner similar to the innovative "One World, One Health" approach. The Observatory provides a platform for knowledge sharing and consensus building among representatives of public policy decision makers and scientists. Its main objectives are to anticipate and prioritize potential issues associated with zoonotic diseases in Quebec, in order to support applicable risk management and climate change adaptation. This article describes what the Observatory is, what it does and outlines its plans for the future.

Ba 1 − x Bi x (Ti 0·9 Zr 0·1 ) 1 − x Fe x O 3 ( x = 0–0·075) ceramics are prepared using a conventional solid state reaction method. X-ray diffraction shows the presence of a single phase. Addition of Bi 3 + and Fe 3 + strongly influences the crystal structure and dielectric properties of the ceramics. The evolution from a normal ferroelectric to a relaxor ferroelectric is emphasized. Ba 0·99 Bi 0·01 (Ti 0·9 Zr 0·1 ) 0·99 Fe 0·01 O 3 ceramic shows a relaxor behaviour at room temperature with Δ T m =12 K. P – E hysteresis loop of the composition, x = 0·007, shows a remanent polarization ( P r ) of 0·5 μ C/cm 2 with a coercive field ( E C ) of 2 kV/cm. Raman spectra of all compounds are performed and correlated well with the X-ray diffraction and dielectric measurement results.

The ferroelectric and piezoelectric properties of Ba1-xNax(Ti0,8Sn0,2)(1-x-)NbxO3 (BTSnNx0.2), the new lead-free ceramic, are investigated. At room temperature, X-ray diffraction (XRD) study suggests that the compositions have a single phase with cubic symmetry. The dielectric study reveals that the material has a ferroelectric or a relaxor behavior. The polarization state is checked by hysteresis and piezoelectric measurements.

The temperature dependence of the real and imaginary parts of dielectric permittivity for (Ba1-xCax)(1-3y/2) BiyTiO3 solid solution prepared using the solid-state reaction technique, suggests that the relaxor character in this solid solution depends strongly on the Bi than on the Ca doping percent.X-ray diffraction analysis show that Bi doping can be fully incorporated into the perovskite lattice of (Ba1-xCax)TiO3. Doping with Bi causes remarkable shift of the maximum of dielectric permittivity (T-m) at low temperatures and the evolution of epsilon'(r) exhibiting strong frequency dispersion. For some compositions, we have observed a typical behavior of a well-known relaxors. On the other hand, we pointed out that the relaxor character is linked principally to the nature of the substituting element and not to the heterogeneity in general. So the Ca element does not have the same effect as the Bi one. (c) 2012 Elsevier Ltd. All rights reserved.

New lead free piezoceramics with the given compositions (1 x)(0.1BaTiO3e0.9NaNbO3) exLiNbO3(0.01 x 0.125) were prepared by solidestate reaction technique. XRD patterns revealed a single perovskite-structured phase only for 0.01 x < 0.05. The dielectric, pyroelectric and piezoelectric responses were investigated for compositions with x 1⁄4 0.01 and 0.02. For both compositions, 3’r exhibited a sharp peak with no frequency dependence (classical ferroelectrics). Losses displayed a strong dispersion at low frequencies in the paraelectric phase which was attributed to Li ionic conductivity in these compositions. The spontaneous polarization was found to be 35 and z22 mC cm 2 for x 1⁄4 0.01 and 0.02 respectively. The transverse piezoelectric coefficient d31 measured for x 1⁄4 0.01 reached value of 37 pC/N at room temperature while the planar coupling factor was about 0.23. 2012 Elsevier Masson SAS. All rights reserved.

Polycrystalline samples of BaTi1−x (Mn0.5Nb0.5) x O3 with x = 0.025, 0.05, 0.075, 0.1, 0.125, 0.15, and 0.175 have been synthesized by the high-temperature solid-state reaction technique. The effects of cationic substitution of manganese and niobium for titanium at B sites of the BaTiO3 perovskite lattice on symmetry and dielectric properties were investigated. X-ray diffraction at room temperature and dielectric permittivity in the temperature range from 85 K to 500 K and frequency range from 100 Hz to 2 × 105 Hz were studied. The evolution from a normal ferroelectric to a relaxor ferroelectric is emphasized. T C or T m decreases when both manganese and niobium are introduced into the lattice of BaTiO3. High dielectric constant of around 9000 at T C = 280 K was found for Ba Ti0.925(Mn0.5Nb0.5)0.075O3 ceramic. A relaxor ferroelectric with ΔT m = 60 K and \( \varepsilon_{\rm{r}}^{\prime } \) of about 3500 at 10 kHz with T m = 150 K was found for the BaTi0.85(Mn0.5Nb0.5)0.15O3 sample.

New lead free piezoceramics with the given compositions (1 - x)(0.1BaTiO(3)-0.9NaNbO(3))-xLiNbO(3) (0.01 <= x <= 0.125) were prepared by solid-state reaction technique. XRD patterns revealed a single perovskite-structured phase only for 0.01 <= x <= 0.05. The dielectric, pyroelectric and piezoelectric responses were investigated for compositions with x = 0.01 and 0.02. For both compositions, epsilon'(r) exhibited a sharp peak with no frequency dependence (classical ferroelectrics). Losses displayed a strong dispersion at low frequencies in the paraelectric phase which was attributed to Li ionic conductivity in these compositions. The spontaneous polarization was found to be 35 and approximate to 22 mu C cm(-2) for x = 0.01 and 0.02 respectively. The transverse piezoelectric coefficient d(31) measured for x = 0.01 reached value of 37 pC/N at room temperature while the planar coupling factor was about 0.23. (C) 2012 Elsevier Masson SAS. All rights reserved.

Effect of doping by Bi and Ca on ferroelectric properties and relaxor character in the (Ba1 xCax)1 3y/2BiyTiO3 solid solution H. Zaghouene , F. Bahri , M. Boujelbene , H. Khemakhem , A. Simon c a Laboratoire des Matériaux Ferroélectriques (LMF), Unité de Physique-Mathématiques 05UR15-04, Université de Sfax, Faculté des Sciences de Sfax (FSS), Route de Soukra km 3.5,B.P. 1171, 3000 Sfax, Tunisie b Laboratoire de l’État Solide, Faculté des Sciences de Sfax, P.B.1171, 3000 Sfax, Tunisie c Institut de Chimie de la Mati ere Condensée de Bordeaux (ICMCB), CNRS, Université de Bordeaux, 87 Avenue du Dr. A. Schweitzer, Pessac F-33608, France

We report an investigation of the local structure in homovalent-substituted BaTi1-xZrxO3 relaxors by a combination of experimental and theoretical methods, namely neutron total scattering, X-ray absorption spectroscopy, and supercell ab-initio calculations. It is shown that unlike Zr atoms, Ti atoms are largely displaced in their octahedra, and are thus associated with strong local dipole moments. Besides, we give evidence that the difference in the size of Ti4+ and Zr4+ cations leads to a significant size mismatch of the Ti-O6 and Zr-O6 octahedra. When they link to form the perovskite structure of BaTi1-xZrxO3, the O6 octahedra undergo slight distortions in order to accommodate their different sizes. It is shown that they are compressed in the direction of Zr neighbors, and expanded in the direction of Ti neighbors. The polar Ti displacements, which are sensitive to the octahedral distortions, then become constrained in their orientation according to the local Zr/Ti distribution. Such constraints impede a perfect alignment of all the Ti displacements as existing in the classic ferroelectric BaTiO3. Our results shed light on the structural mechanisms that lead to disordered Ti displacements in BaTi1-xZrxO3 relaxors, and probably in other BaTiO3-based relaxors with homovalent substitution.

The (Ba0.95Ca0.05)0.8875Bi0.075TiO3 ceramic composition was prepared using the conventional mixed-oxide technique. X-ray diffraction at room temperature and dielectric permittivity in the temperature range from 85 to 450K and frequency range from 102 to 2×105Hz, respectively, were studied. The X-ray spectra were investigated by profile refinement technique with the use of specialized software at room temperature, the (Ba0.95Ca0.05)0.8875Bi0.075TiO3 composition crystallizes in quadratic perovskite structure. The dielectric measurements show classical ferroelectric behavior. The pyroelectric and piezoelectric results confirm the dielectric measurements. The pyroelectric coefficient is about 69.2nC/cm2K at the transition temperature (TC=367K). The piezoelectric constant is d31=31.1pC/N and the electromechanical coupling factor is kP=0.14679. Raman spectra of (Ba0.95Ca0.05)0.8875Bi0.075TiO3 ceramic were taken at various temperatures and measured over the wave number range from 50 to 1000cm−1. All the Raman bands were assigned as the transitional modes of Ba2+, Ca2+, Bi3+ and Ti4+ cations. The temperature evolution of Raman spectra across the transition shows an important evolution characterizing the disorder of the high temperature phase.

We report a large d31 piezoelectric coefficient and corresponding electromechanical coupling factor, Kp, of 0.5Ba(Zr0.2Ti0.8)O3–0.5(Ba0.7Ca0.3)TiO3 (BCTZ50) and 0.68Ba(Zr0.2Ti0.8)O3–0.32(Ba0.7Ca0.3)TiO3 (BCTZ32) lead-free piezoceramics. The piezoelectric coefficient, d31, reaches a high value of 200 pC/N for BCTZ50 at room temperature which is comparable to the one of the soft PZT. This confirms the previously reported d33 for the same material. A useful way to achieve such performances at the expense of a smaller thermal budget is suggested, enabling better control of the ceramics composition and microstructure. Based on pyroelectric and ferroelectric hysteresis loops measurements, we show that such outstanding properties are likely due to the high flexibility of polarization under thermal and electric stresses.

Lead-free (1 − x)NaNbO3/xBa(Ti0.5Sn0.5)O3 (x = 0.1, 0.125, 0.15, 0.175, 0.2, and 0.3) ceramics were elaborated by the conventional ceramic technique. Sintering has been made at 1523 K for 2 h. The crystal structure was investigated by X-ray diffraction with CuKα radiation at room temperature. As a function of composition, these compounds crystallize with tetragonal or cubic symmetry. Dielectric measurements show that the materials have a classical ferroelectric behavior for compositions in the range 0.10 ≤ x ≤ 0.15 and relaxor one for compositions in the range 0.15 < x ≤ 0.30. Temperatures T C or T m decrease as x content increases. The ferroelectric behavior has been confirmed by hysteresis characterization. For x = 0.1, a piezoelectric coefficient d 31 of 42.146 pC N−1 was obtained at room temperature. The evolution of the Raman spectra was studied as a function of temperature for x = 0.1.

The main objective of this paper is to study dielectric, ferroelectric, pyroelectric and piezoelectric proprieties of BaTi0.95(Ni1/3Nb2/3)0.05O3. From dielectric experiments, a single ferroelectric transition temperature of about 300K was found. The ferroelectric hysteresis loops were recorded versus temperature evidencing a saturation polarisation of about 4μC/cm2 and a coercive field of 0.97kV/cm at the lowest temperature. The most promising result for BaTi0.95(Ni1/3Nb2/3)0.05O3 is its effective piezoelectric coefficient d31which reaches 55pCN−1 at room temperature.

We have processed Ba(1+x/2)LaNb(5-x)Ti(x)O(15) thin films using radio-frequency magnetron sputtering. Using XRD, SEM, x-ray microprobe and RBS, the polycrystalline films have been optimized as to reach the nominal composition. Dielectric experiments have been performed on ceramics and thin films for frequencies between 100 Hz and 5 MHz in the temperature range 100-420 K. In the most stoichiometric films, relaxor behaviour is evidenced whose features are similar to those of ceramics of the same composition. Such an agreement between ceramics and thin films relaxors is only rarely reported in lead-free materials. Moreover, the relaxor state was reported in perovskite films and our present report broadens the range of structures in which it can occur.

New ferroelectric ceramics of ABO3 perovskite type were synthesized in the Ba(Ni1/3Nb2/3)xTi1−xO3 (0≤x≤0.2) system by solid state reaction technique. The effect of the replacement of titanium by nickel and niobium in the B site on structural and dielectric properties was investigated. For this, we have use X-ray diffraction and dielectric characterizations. Samples in cubic phase were generally obtained with a sintering temperature of 1350°C. Dielectric measurements revealed that the very small change in composition by the substitution of titanium by nickel and niobium in the BaTiO3 has a strong influence on the dielectric proprieties: fast decreasing of TC or Tm (for BaTiO3 TC=340K, for x=0.06, TC=270K and for x=0.16, Tm=150K). The evolution from classic ferroelectric behavior for (0≤x<0.1) to relaxor behavior for (0.1≤x≤0.2) is emphasized.

Several Niobium oxides of formula Ba2LnFeNb4O15 (Ln = La, Pr, Nd, Sm, Eu, Gd) with the "tetragonal tungsten bronze" (TTB) structure have been synthesised by conventional solid state methods. The neodymium, samarium and europium compounds are ferroelectric with Curie temperature ranging from 320 to 440 K. The praseodymium and gadolinium compounds behave as relaxors below 170 and 300 K respectively. The praseodymium, neodymium, samarium, europium and gadolinium compounds exhibit magnetic hysteresis loops at room temperature originating from traces of a barium ferrite secondary phase. The presence of both ferroelectric and magnetic hysteresis loops at room temperature allows considering these materials as composites multiferroic. Based on crystal-chemical analysis we propose some relationships between the introduction of Ln3+ ions in the TTB framework and the chemical, structural and physical properties of these materials.

The pair distribution functions (PDF) of BaTi1-xZrxO3 (BTZ) relaxors (x=0.25,0.32,0.35), as well as those of the end members BaTiO3 and BaZrO3, were determined at 300 K from neutron powder scattering data. In the relaxors, the PDF provides direct evidence that the Ti and Zr atoms do not occupy the equivalent octahedral sites expected from the crystallographic cubic perovskite structure. It is shown that the TiO6 and ZrO6 octahedra in BTZ relaxors are instead similar to those observed in BaTiO3 and BaZrO3, respectively. In BaZrO3, the Zr atoms lie at the center of regular oxygen octahedra, forming nonpolar ZrO6 units. In the tetragonal ferroelectric phase of BaTiO3, the distribution of Ti-O distances within TiO6 octahedra is found compatible with a displacement of the Ti atoms in the [111](p) direction of the pseudocubic perovskite cell. We conclude that the local polarization in BTZ relaxors is mainly due to the displacements of the Ti atoms and that moreover the Ti displacements are very similar in BTZ relaxors and in the classical ferroelectric BaTiO3.

New ferroelectric ceramics of ABO(3) perovskite type were synthesized in the BaTi1-x(Zn1/3Nb2/3)(x)O-3 system by solid state reaction technique. The effect of the replacement of titanium by zinc (Zn) and niobium (Nb) in the B cationic site on structural and dielectric properties were investigated. As a function of composition, these compounds crystallize with tetragonal or cubic symmetry. The material is classical ferroelectric for 0 <= x <= 0.05 and presents a relaxor behavior for 0.075 <= x <= 0.2 and for 0.75 <= x <= 0.975. Dielectric permittivity in the temperature range from 85 to 500 K with frequencies range from 0.1 to 200 kHz, was studied.In the region when 0.75 <= x <= 0.975, Delta T-m presents the important values which go more then 100 K for BaTi0.05(Zn1/3Nb2/3)(0.95)O-3 composition with values of T-m near room temperature. These values make these ceramic compositions in the families of relaxors with interest properties for applications. (c) 2007 Elsevier B.V. All rights reserved.

The hysteresis, piezoelectric and pyroelectric properties were measured in the temperature range near the ferroelectric–paraelectric phase transition. The BaTi0.9(Fe1/2Nb1/2)0.1O3 ceramic exhibits typical ferroelectric P –E hysteresis behavior with a remanant polarization, Pr, of about 7.52 μC/cm2 detected at 155 K. The electromechanical properties of this composition were measured using the resonance method. The ceramic provides high piezoelectric performance at the temperature of transition (Tmax = 216 K): the piezoelectric constant is d31 = 140 pC/N and the electromechanical coupling factor was kP = 22%. The pyroelectric study confirms the dielectric and ferroelectric measurements. The pyroelectric coefficient is about 125 nC/cm2 K at Tmax. Raman spectra of BaTi0.9(Fe1/2Nb1/2)0.1O3 ceramic were taken at various temperatures and measured over the wave number range from 150 to 1300 cm–1. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

This paper reports the structural and dielectric properties of Ba1 − x Ca x Ti 1 − y (Zn 1/3 Nb 2/3 ) y O 3 ceramics with y is fixed to 0.2 and x = 0.2 and 0.3. Single-phase solid solutions of the simples were determined by X-ray diffraction. For the solid solution, BaTi 1 − y (Zn 1/3 Nb 2/3 ) y O 3 , the evolution of dielectric behaviour from a sharp ferroelectric peak (for y < 0.075) and to ferroelectric relaxor (for 0.075 < y < 0.2) was observed with increasing of Zn and Nb concentration but in this case the temperature of the maximum of dielectric permittivity T m and Δ T m are lowers. To modulate this relaxor character we have substitute the Ba by Ca to increase T m and Δ T m .