The domain morphology and crystal structure of (1−x)(Bi1/2Na1/2)TiO3xBaTiO3 lead-free piezoelectric ceramics were systematically studied with transmission electron microscopy for compositions x=0.04through 0.11. It was found that the ceramics with compositions x<0.06 display a R3csymmetry with ferroelectric domains of ∼100 nm forming complex structures at room temperature. Only nanodomains with faint contrast were observed in the compositions of 0.07≤x≤0.09. The presence of weak 1/2 (ooe)superlattice diffraction spots and absence of 1/2 (ooo) ones (o stands for odd and e stands for even miller indices) seem to suggest a P4bm symmetry at room temperature. The morphotropic phase boundary composition x=0.06 showed mixed R3c and P4bm phases. Large lamellar ferroelectric domains with P4mm symmetry were found to dominate in the ceramic of x=0.11. The observed domain structure correlates extremely well with the frequency dispersion of dielectric constant at room temperature and a new concept "relaxor antiferroelectric" was proposed to describe the dielectric behavior of compositions 0.07≤x≤0.09. These results are summarized in a phase diagram for unpoled ceramics in the (1−x)(Bi1/2Na1/2)TiO3xBaTiO3binary solid solution system.

Via a combination of various experimental and theoretical techniques, a peculiar, identical temperature scale T* is found to exist in all complex lead-based relaxor ferroelectrics. T* corresponds to a nanoscale phase transition due to random fields. Interestingly, T* also exists in other oxides with extraordinary properties, such as giant magnetoresistivity or superconductivity. By analogy with such latter systems, the giant piezoelectricity related to relaxors might originate from proximity competing states effect.

Graphene single layers grown by chemical vapor deposition on single crystal Cu substrates are subject to nonuniform physisorption strains that depend on the orientation of the Cu surface. The strains are revealed in Raman spectra and quantitatively interpreted by molecular dynamics (MD) simulations. An average compressive strain on the order of 0.5% is determined in graphene on Cu(111). In graphene on Cu (100), MD simulations interpret the observed highly nonuniform strains.

BaTiO 3 crystals were studied by means of the acoustic emission during thermal cycling through 300–700 K range. In addition to pronounced acoustic emission at the ferroelectric phase transition temperature Tc≈400 K, also nucleation of nanoclusters was detected at somewhat smeared Burns temperature Td≈530–570 K and their local freezing at T∗≈506 K. Bias electric field shifts the T∗ and Tc linearly up, T∗ more steeply than Tc. Except for its much faster cluster dynamics than that of classical relaxor materials, BaTiO3 shows many relaxor-like features in its paraelectric phase.

Aqueous solubilities of two- to four-ring solid polycyclic aromatic hydrocarbons (PAHs) (naphthalene, anthracene, 1,2-benzanthracene, triphenylene, and p-terphenyl) were measured at temperatures within 313 K to the PAH melting point and pressures within the range (4 to 8) MPa by dynamic method combined with gas chromatography/mass spectrometry. A novel feature of the apparatus was the use of a capillary restrictor to minimize the system volume downstream of the sampling point. The results for naphthalene and anthracene compare favorably with the literature data whereas the solubilities of 1,2-benzanthracene, triphenylene, and p-terphenyl in pressurized hot water are reported for the first time. The solubilities (equilibrium mole fractions, x 2) of PAHs are discussed in terms of temperature and hydrocarbon structure. Mean values of the relative change in the PAH solubility with temperature, (∂ ln x 2/∂T)σ, range from 5.4 × 10-2 K-1 in naphthalene to 7.2 × 10-2 K-1 in p-terphenyl. The ln x 2 versus T plot for 1,2-benzanthracene is curved in the opposite direction as compared with the plots for anthracene, triphenylene, and p-terphenyl.