The critical behaviour of an anisotropic n-vector model with purely Ising-like coupling is studied on the FCC lattice by means of high-temperature series. The model includes the s = i (n = 1) and s = m (n = 3) Ising models as special cases and exhibits rigorously mean-field behaviour at n = CO. The crossover region, l / n --f 0, t = (1t./cC) + 0, is examined in detail. The susceptibility exponent y remains Ising-like for all finite n. The critical temperature and critical susceptibility amplitude vary as lin.

Photorefractive effects are, for the first time to our knowledge, observed in single-domain tetragonal BaTiO3 fibers fabricated by the laser pedestal method. The diameter and length of the fiber are 250 μm and 2 mm, respectively. The photorefractivity is confirmed both by beam amplification through two-wave mixing and holographic image storage.

Mechanical poling was applied to a BaTiO3 single crystal grown by the top-seeded solution growth (TSSG) method to remove its 90° domain walls, and then four-step electrical poling was applied to rearrange the 180° domain configuration. In each of these steps, the dielectric constant (from 50 kHz to 10 MHz) was measured by using an impedance analyzer, and the 180° domains were observed by the etching method. The dielectric spectra were confirmed to vary with rearrangement in 180° domain configuration. Dielectric constant εc in the 〈001〉 direction was 130 at 100 kHz and 58 at 10 MHz. Dielectric constant εa in the 〈100〉 direction was 4700 at 100 kHz and 1900 at 10 MHz.

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The pseudobinary phase diagram of BinSrCaCu3−nOy was determined on the line 1≤n≤2 upon which the low Tc superconductor phase [Bi2(Sr,Ca)3Cu2Oy] and the semiconductor phase [Bi2(Sr,Ca)2CuOy] are located. The liquidus line of the superconductor phase was found to lie in the region 1.6≤n≤1.875. A small quantity of transparent crystal was found even in the melting phase, which suggests that samples with these compositions do not melt homogeneously. Therefore, single crystals or single-phase superconductor materials apparently can be grown from the liquid phase by obtaining a homogeneous melt in this region.