Structure and electrical properties of Eu-doped SrBi2Nb2O9 ceramics

Structure and dielectric properties of Eu-doped SrBi2Nb2O9 ceramics (with 0, 20 and 35 at.% of Eu), prepared by the solid-state method and sintering, were investigated. XRD, FTIR and SEM measurements were provided to validate the characteristic structural features of the obtained ceramics. For all samples, the orthorhombic structure was identified through XRD analysis. SEM results confirmed that the fabricated samples have relatively dense structure with rod- and plate-like grains typical for Aurivillius layered structures. Dielectric results showed that the doping with Eu decreases dielectric constant and reduces dielectric loss. Movement of the dielectric peak towards higher temperatures appearing at about 400?C with increase of frequency indicates on relaxor behaviour of the sample with 35 at.% of Eu.

Effects of Lanthanum Substitution on Dielectric, Ferroelectric and Electro-Optic Properties of Slim-Loop PLZT Ceramics

Highly transparent lead lanthanum zirconate titanate (Pb1−xLax)(Zr0.65Ti0.35)1-x/4O3(x=0.096-0.1) electro-optic ceramics were prepared by the hot pressing method. The ceramics exhibited transparency as high as 67% at 632.8nm (close to the theoretical value). The effects of lanthanum substitution on the phase structure, microstructure, dielectric, ferroelectric, optical and electro-optic properties of PLZT were examined systematically. The XRD results indicated that all the compositions were single perovskite phases, and La substitution decreased the lattice constant and unit-cell volume. The dielectric results showed that the Tmaxand εmaxdecreased with La content increasing. The hysteresis loops showed that the La content reduced saturate polarization (Ps), remnant polarization (Pr) and coercive field (Ec). Moreover, the half-wave voltage and EO coefficient R was enhanced and reduced respectively with increasing La.

Spin injection behavior in conducting polymer coated superparamagnetically functional microstructures

A nanoferrite superparamagnetic system synthesized through co-precipitation method and subsequently dispersed in a medium of de-ionized water was encapsulated with a matrix polymer under constant sonication using chemical oxidative polymerization technique. The polymer coated functional microstructure thus obtained shows enhanced magnetization as evidenced from the results reported elsewhere. The magnetic core crystal growth and anti-spin canting hypothesis were given to be the most general justification behind the unusual enhancement in magnetization and more specifically the rationale could understand recently in accordance with spin injection behavior in functional core-shell microstructures. In this paper, an attempt has been made to correlate the previous magnetization results with spin injection behavior, in conjunction with the thermo gravimetric and dielectric results.

3D-Simulation of Void Formation, Growth and Migration under Electromigration

The 3D Monte Carlo scheme is proposed for simulation of simultaneous self-consistent current redistribution, surface diffusion, drift and void migration and coalescence at the interface metal/dielectric. Results of simulation as well as simple phenomenological model demonstrate a possibility of trapping at and migration along the grainboundaries (GBs). Critical size of “detrapping” after coalescence has been estimated.