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We present electric and magnetic properties of 0.8Pb(Fe1/2Nb1/2)O3–0.2Pb(Mg1/2W1/2)O3 films epitaxially grown on (001) SrTiO3 substrates using pulsed laser deposition. A narrow deposition window around 710 °C and 0.2 mbar has been identified to achieve epitaxial single-phase thin films. A typical Vogel–Fulcher relaxorlike dielectric and magnetic susceptibility dispersion is observed, suggesting magnetoelectric relaxor behavior in these films similar to the bulk. We determine a magnetic cluster freezing temperature of 36 K, while observing weak ferromagnetism via magnetic hysteresis loops up to 300 K. [ABSTRACT FROM AUTHOR]

Phases, domain configuration, and properties of 0.65Pb(Mg1/3Nb2/3)O3–0.35PbTiO3 ceramics with grain sizes of 4 and 0.15 μm have been studied. The average phase is monoclinic Pm in coexistence with tetragonal. An evolution from micron-sized lamellar domains towards submicron/nanometer sized crosshatched domains is found with the decrease in size, which results in electrical relaxor type behavior and hindered switching. This is proposed to be associated with the slowing down of the relaxor to ferroelectric transition that causes the long time presence of an intermediate domain configuration. Nevertheless, a high sensitivity piezoelectric submicron-structured material is obtained under tailored poling (d33∼300 pC N-1). [ABSTRACT FROM AUTHOR]

A detailed Rietveld analysis of x-ray data, collected at roomtemperature, was done on ceramics with controlled grain size between 100 nm and 4 μm for (PbMg1/3Nb2/3O3)0.80–(PbTiO3)0.20 (PMN-PT20), i.e., a compound at the border of the so-called morphotropic phase boundary. With size reduction the polarization rotates within the monoclinic plane from MB, i.e., Px=Py>Pz to MA, i.e., Px=Pyz, and finally reaches a rhombohedral phase, i.e., Px=Py=Pz, below a critical value of ∼200 nm without diminishing the amplitude of the polarization. This study provides an easy way to tailor the direction of polarization of these materials [ABSTRACT FROM AUTHOR]

In order to explore the field-induced evolution from the relaxor phase towards the ferroelectric phase (RF transition) in hot-pressed 6.5/65/35 PLZT relaxor-ferroelectric ceramics, a Field-Cooled-Field-Heated (FC/FH) spontaneous polarization was measured as a function of the bias electric field and temperature. Analysis was performed within the framework of the spherical random-bond-random-field (SRBRF) model. [ABSTRACT FROM AUTHOR]

An exceptionally high dielectric constant was obtained by making use of the conductive percolative phenomenon in all-ceramic composite, comprising of Pb2Ru2O6.5 with high electrical conductivity denoted as the conductive phase and ferroelectric 0.65Pb(Mg1/3Nb2/3)O3–0.35PbTiO3 (PMN-PT) perovskite systems. Structural analysis revealed a uniform distribution of conductive ceramic grains within the PMN-PT matrix. Consequently, the dielectric response in the PMN-PT-Pb2Ru2O6.5 composite follows the predictions of the percolation theory. Thus, close to the percolation point exceptionally high values of the dielectric constant were obtained—values higher than 105 were detected at room temperature at 1 kHz. Fit of the data, obtained for samples of different compositions, revealed critical exponent and percolation point, which reasonably agree with the theoretically predicted values. [ABSTRACT FROM AUTHOR]

The elastic strain of lead-free relaxor K0.5Na0.5NbO3–SrTiO3 ceramic system, induced by applied electric fields with amplitudes up to 40 kV/cm, has been investigated. The strain response, being similarly low (order of 10-5) as in the classical lead magnesium niobate relaxor, is shown to be of solely electrostrictive origin, as a pure quadratic relation holds between induced strain and electric polarization. The strain dependence on the SrTiO3 content is presented and discussed. Furthermore, electrostrictive coefficients are shown to be constant over a broad temperature range and, similar to dielectric properties, independent of electric-field cycles, which suggests possible applications of this translucent, high-dielectric constant, and environmental-friendly ceramic system. [ABSTRACT FROM AUTHOR]

This note describes a hydropneumatic low-speed lowering mechanism which provides variable pulling rates down to 0.05 mm per hour. [ABSTRACT FROM AUTHOR]

This note describes the surface treatment of a mirror furnace, made from a block of aluminum. The method offers an inexpensive way to obtain temperatures up to 2100 °C. [ABSTRACT FROM AUTHOR]