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The effect of postsintering annealing on the dielectric and piezoelectric responses in lead-zincniobate (PZN)-based ferroelectric ceramics was systematically studied in this work. Sintered PZN ceramics with the same composition were annealed at temperatures from 700 to 900 °C from 30 min to 24 h in various atmospheres. As a result, significant improvements in the dielectric and piezoelectric responses were observed in this system. After annealing, there was a huge increase of up to 130% in the dielectric constants, especially near the temperature of maximum dielectric constant. While the dielectric peaks became sharper and less diffuse, there was almost no change in frequency dispersion. Similar large improvements in the piezoelectric properties such as the coupling factor and piezoelectric constant were also observed. Optimized parameters, such as d[sub 33] = 642 pC/N, d[sub 31] = - 256 pC/N, k[sub p] =48% and ∈[sub m] = 28 000, were achieved by annealing at 850 °C in an O[sub 2]-rich atmosphere for 4-8 h. The observed improvement in the electrical properties can be attributed to an extrinsic contribution induced by domain wall motion. After annealing, the pinning effects caused by oxygen vacancies and internal stress on domain wall motion were largely reduced or eliminated, therefore a significantly reduced coercive field, an increased polarization level, and a greatly increased dielectric constant were observed in the PZN-based ferroelectric ceramics. [ABSTRACT FROM AUTHOR]

We theoretically predict and numerically simulate the discrete plasmonic Talbot effect in dielectric graphene plasmonic waveguide (DGPW) arrays at THz wavelengths. The super-modes in DGPW arrays are analyzed by using super-mode theory and the field intensity distributions in the designed DGPW arrays are explained by the superposition of different super-modes and simulated by using commercial software (COMSOL) based on finite element method (FEM). The discrete plasmonic Talbot effect is realized by superposition of different super-modes. The Talbot distance can be actively tuned by varying the Fermi energy of graphene and it decreases monotonically with increasing Fermi energy. In addition, it is found that the Talbot distance increases with the period of the DGPW arrays. Simulation results show a good agreement with the theoretical analysis. [ABSTRACT FROM AUTHOR]

Making use of defects modification to P(VDF-TrF'E) via either high energy electron irradiation treatment or copolymerizing VDF-TrFE with a small amount of chlorinated monomer to form a random terpolymer, we demonstrate that high electromechanical responses can be realized in P(VDF-TrFE) based polymers. It will be shown that in the stretched and irradiated 68/32 mol% copolymer, a transverse strain of 4.5% and a transverse electromechanical coupling factor k31 of 0.65 can be induced under a field of 85 MV/m. In addition, the irradiated copolymer also exhibits a high elastic energy density, &Sim;1 J/cm³. For PVDF based terpolymers such as P(VDF-TrFE-CFE) terpolymer (CFE: chlorofluoroethylene), an electrostrictive strain of more than 7% can be obtained. To elucidate the microstructure changes due to the defects modification in P(VDF-TrFE) based polymers, synchrotron X-ray measurement was carried out on the irradiated copolymers and the results show that, the irradiation converts the polar-phase into a non-polar phase. In addition, X-ray date show that the polar-phase can be induced, at the expense of the non- polar phase, by external fields, confirming that the field induced conformation change is responsible for the observed high electromechanical responses. Although the modified PVDF based polymer exhibits the highest room temperature dielectric constant (60 versus below 10), it is still far below those in the inorganic materials. Experimental results show that by using delocalized electrons in conjugated bonds an all-organic composite with a dielectric constant more than 400 can be achieved. As a result, a strain of near 2% with an elastic energy density higher than 0.1 J/cm³ can be induced under a low applied field of 13 V/μm. The strain is proportional to the applied field and the composite has an elastic modulus near 1 GPa. [ABSTRACT FROM AUTHOR]

Abstract: PVD CuMn self-forming barrier (SFB) approach was investigated on 300mm wafers as an alternative to conventional PVD Ta/Cu metallization. Cu fill on very aggressive dual damascene features targeted for beyond 32nm node was evaluated along with integrated electrical and reliability performance on low-k (k =2.6) interlayer dielectric (ILD). [Copyright &y& Elsevier]