The effective valence, of mobile cations (Fe2+, Fe3+) in semiconducting Fe3O4 was determined at elevated temperatures via Tubandt-type electrotransport experiments in association with the literature data on the cation diffusivity and total electrical conductivity. It has been found that the value for varies systematically from below 2 up to 3 with oxygen partial pressure at a fixed temperature. The effective valence is determined not only by the mobility difference of Fe2+ and Fe3+ ions but also by the cross effect between the cations and electrons upon their transfer . A value of between 2 and 3 may be attributed to the mobility difference between Fe2+ and Fe3+ ions even in the absence of the cross effect, but the values of < 2 clearly indicate that the cross effect is in play in Fe3O4.

Sol-gel processing of La2Zr2O7 (LZO) buffer layers on biaxially textured Ni–1.7% Fe–3% W alloy substrates using a continuous reel-to-reel dip-coating unit has been studied. The epitaxial LZO films obtained have a strong cube texture and uniform microstructure. The effects of increasing the annealing speed on the texture, microstructure, and carbon content retained in the film were studied. On top of the LZO films, epitaxial layers of yttria-stabilized zirconia and Ceria (CeO2) were deposited using rf sputtering, and YBa2Cu3Ox (YBCO) films were then deposited using pulsed laser deposition. Critical current densities (Jc) of 1.9 MA/cm2 at 77 K and self-field and 0.34 MA/cm2at 77 K and 0.5 T have been obtained on these films. These values are comparable to those obtained on YBCO films deposited on all-vacuum deposited buffer layers and the highest ever obtained using solution seed layers.

CuO nanocrystals of three different sizes 3.5, 6.5, and 10.0 nm were synthesized by a novel electrochemical route. Quantum size effects in these nanocrystals are evident from the optical absorption spectra. The optical absorption feature is observed to be blue shifted by about 1 eV with size reduction. The CuO q-particles were found to be single-phased and very stable as far as the size and phase is concerned.

Sn-doped BaO–TiO2–ZnO (BTZ) microwave ceramic materials were investigated as a function of SnO2 content. Addition of a small amount of SnO2 (0.01–0.06 wt%) lowered the sintering temperature of the system to 1160 °C and also greatly reduced the dielectric loss (tan δ), which is closely related to the insulation resistivity. The Sn-doped BTZ materials were found to have excellent dielectric properties at 1 GHz with dielectric constant Ε ≈tangent tan δ ≤ 1 × 10−4, temperature coefficient of dielectric constant, αΕ = 0 ± 30 ppm/°C, and volume resistivity ρv ≥ 1013 ω cm.

AlN/VN superlattices with different periods were studied using x-ray diffraction and transmission electron microscopy (TEM). A phase transformation of the AlN from an epitaxially stabilized rock-salt structure to a hexagonal wurtzite structure was observed for an AlN layer thickness greater than 4 nm. A structural model is proposed on the basis of TEM results for the orientation of the transformed phase. The VN layer grown on top of the hexagonal AlN was observed to be reoriented compared to that in the stabilized B1-AlN/VN. The VN nucleated by taking the w-AlN(002) plane as its (111) plane instead of the (002) plane.

The complex relative permittivity ∈γ and permeability μγ of microcoiled carbon fibers (MCCFs) imbedded in paraffin wax were measured at Ku band frequencies (12.4–18 GHz). Both the real and imaginary parts of the complex relative permittivity of the MCCFs/paraffin wax composite decreased with increase of the frequency. The real part of the complex relative permeability of the composite increases with increase of the frequency, and the imaginary part is nonzero and nearly constant over the measured frequency range. The dielectric loss tangent (tan δ∈), the magnetic loss tangent (tan δm), and amplitude attenuation factor (α) were determined as well. On the basis of the experimental results, the MCCFs/paraffin wax composite is mainly a kind of dielectric lossy material with small magnetic loss and diamagnetism in the Ku band.