Domain wall contribution to dielectric and piezoelectric responses in 0.65Pb(Mg1/3Nb2/3)-0.35PbTiO(3) ferroelectric ceramics

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effect of oxidizing atmosphere on ferroelectric and piezoelectric response of CaBi2Nb2O9 thin films

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Experimental and theoretical study on the piezoelectric behavior of barium doped PZT

An experimental and theoretical study of the ferroelectric and piezoelectric behavior of PZT doped with barium is presented. Ab initio perturbed ion calculations was carried out. The properties, such as remnant polarization, coercive field and the coupling factor of the PZT at constant sintering temperature was compared with the Zr4+/Ti4+ ions dislocation energy and the lattice interaction energy. An agreement between the experimental and theoretical results, with a decrease of the interaction energy and an inversion of the energy stability from tetragonal to rhombohedral phase was observed. (C) 1999 Kluwer Academic Publishers.

Experimental and theoretical study of the ferroelectric and piezoelectric behavior of strontium-doped PZT

Theoretical data using ab initio perturbed ion calculation were compared with ferroelectric and piezoelectric experimental data of strontium doped PZT. Various concentrations of SrO in PZT at constant temperature and sintering time were carried out. Experimental results, such as the remanent polarization, P-R of 6.9-8.9 muC/Cm-2, the coercive field, E-C of 6.6-7.8 kVcm, and the planar coupling factor, Kp of 0.45-0.53, were compared with the energy of Zr4+ and Ti4+ ion dislocation and the lattice interaction energy which show that strontium increment in PZT alter the energies and increase the values of piezoelectric and ferroelectric variables. Calculations of lattice energy of the rhombohedral phase show that a phase non-stability is coincident with increasing experimental values of the P-R, E-C and Kp. (C) 2001 Elsevier B.V. Ltd. All rights reserved.

Influence of microwave energy on structural and piezoelectric response of Bi 4Ti 3O 12 ceramics

Bismuth titanate ceramics (Bi 4Ti 3O 12) with 10 wt% in excess of bismuth (BIT10) were prepared by the polymeric precursor method and sinterized in microwave (MW) and conventional furnaces (CF). The effect of microwave energy on structural and electrical behavior of BIT10 ceramics was investigated by means of X-ray diffraction (XRD), Scanning electron microscopy (SEM) and electrical measurements. The results of the BIT10 ceramics processed in the microwave furnace (MW) showed a high structural organization compared to conventional treatment (CF). Size of grains and dieletrical properties are influenced by annealing conditions while coercitive field is not dependent on it. The maximum dielectric permittivity (12000) was obtained for the sample sintered in the microwave furnace. Piezoelectric force microscopy images reveals that in-plane response may not change its sign upon polarization switching, while the out-of-plane response does with the influence of microwave energy. Copyright © 2010 American Scientific Publishers All rights reserved.

Morphotropic phase boundary and electrical properties of 1-x[Bi 0.5Na0.5]TiO3 -xBa[Zr0.25Ti 0.75]O3 lead-free piezoelectric ceramics

Lead-free solid solutions (1-x)Bi0.5Na0.5TiO 3 (BNT)-xBaZr0.25Ti0.75O3 (BZT) (x=0, 0.01, 0.03, 0.05, and 0.07) were prepared by the solid state reaction method. X-ray diffraction (XRD) and Rietveld refinement analyses of 1-x(BNT)-x(BZT) solid solution ceramic were employed to study the structure of these systems. A morphotropic phase boundary (MPB) between rhombohedral and cubic structures occured at the composition x=0.05. Raman spectroscopy exhibited a splitting of the (TO3) mode at x=0.05 and confirmed the presence of MPB region. Scanning electron microcopy (SEM) images showed a change in the grain shape with the increase of BZT into the BNT matrix lattice. The temperature dependent dielectric study showed a gradual increase in dielectric constant up to x=0.05 and then decrease with further increase in BZT content. Maximum coercive field, remanent polarization and high piezoelectric constant were observed at x=0.05. Both the structural and electrical properties show that the solid solution has an MPB around x=0.05. © 2012 Elsevier Ltd and Techna Group S.r.l.

An Experimental Study on the Effect of Temperature on Piezoelectric Sensors for Impedance-Based Structural Health Monitoring

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)