In this paper an incremental constitutive theory for the deformation due to switching in ferroelectrics is applied to predict the fracture toughness anisotropy in these materials after mechanical poling. Mechanical poling of an initially unpoled specimen differs from electrical poling in that only mechanical stresses are applied to the material. Therefore, no electrical polarization can develop...

High permeability and high permittivity are hard to be achieved simultaneously, either in single-phased materials or in composite materials, such as ferrite-ferroelectric ceramic composites and ferrite-metal percolative composites. In this work, ultra-low percolation threshold is achieved in NiZnCu ferrite-Ag cofired ceramics, which endows the composite with both high permeability and high perm...

Lead Zirconate ceramics are technically and commercially important piezoelectric materials. It is an antiferroelectric ceramic. The antiferroelectric (AFE) to ferroelectric transition, under the application of a strong electric field, leads to significant energy storage for a dc field. This feature of PbZrO3 makes it a candidate material for energy storage applications. In the present study, th...

We have investigated the effects of electrical conductivity of the constituents on the dielectric and piezoelectric properties of ferroelectric 0-3 composites. The time-dependent internal electric fields are first derived, which can be induced by an applied ac field in dielectric measurement or stress in piezoelectric measurement. Our previously developed model fC. K. Wong, Y. M. Poon, and F. G...

Comparative studies of the pyroelectric properties and structural features sodium niobate sodium-potassium ceramics obtained under different technological conditions for synthesis have been carried out. X-ray phase analysis revealed existence an additional with chemical formula NaNb 10 O 18 in ceramic samples that do not exhibit ferroelectric properties. It is shown temperature material determi...

Barium titanate ceramic powders have been incorporated in polyamide 11 to form homogeneous dispersion of particles in the matrix. Barium titanate/polyamide 11 nanocomposites have been synthesized using a solvent casting method with ultrasonic stirring to homogeneously disperse inclusions in the matrix. Composites with volume fraction of barium titanate / ranging from 0.01 to 0.4 were elaborated...

Perovskite oxide ceramics have found wide applications in energy storage capacitors, electromechanical transducers, and infrared imaging devices due to their unique dielectric, piezoelectric, pyroelectric, and ferroelectric properties. These functional properties are intimately related to the complex displacive phase transitions that readily occur. In this study, these solid-solid phase transit...

Potassium polytitanates are new promising type of ferroelectric ceramic materials with high ionic conductivity, highly polarizable structure and extremely high permittivity. Its structure is formed by [TiO6] octahedral units to layers with mobile potassium and hydroxonium ions in-between. The treatment in solutions containing nickel ions allows forming heterostructured materials which consist o...

The X-ray absorption near-edge structures (XANES) at the Ti K-edge of Pb1-xLaxTiO3 ferroelectric ceramic compounds are analyzed as a function of the sample composition. The calculated XANES spectra using the FEFF8.2 code are compared with experimental data. Experimental results show that the local distortion around Ti atoms has different composition dependence as compared to the crystallographi...

Efficient driving of piezoelectric materials is desirable when operating transducers for biomedical applications such as high intensity focused ultrasound (HIFU) or ultrasound imaging. More efficient operation reduces the electric power required to produce the desired bioeffect or contrast. Our preliminary work [Cole et al. Journal of Physics: Condensed Matter. 2014;26(13):135901.] suggested th...