Materials Literature
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The spatially local and long wavelength properties of diblock copolymer melts are studied using the polymer reference interaction site model theory. Two new molecular based closure approximations, the ‘‘reference-molecular mean spherical approximation’’ (R-MMSA) and the ‘‘reference-molecular Percus–Yevick’’ (R-MPY) ap…
Electrical conductivity, magnetic susceptibility, and electron-spin-resonance studies are reported in polyaniline and its derivatives poly(o-toluidine), poly(o-ethylaniline), and poly(o-propylaniline). It is shown that substituents on the ${\mathrm{C}}_{6}$ rings of the polymer backbone lead to decreased conductivity,…
Fe3O4 thin films were reactively sputtered onto 〈100〉 and 〈110〉 MgO substrates. X-ray diffraction data indicate single crystal Fe3O4 films under a tensile stress. Magnetization data show good agreement with bulk Fe3O4 for Ms, but also show the presence of a large anisotropy component manifest in the lack of saturation…
Infrared emission from highly vibrationally excited NO2, prepared by collision induced internal conversion, can be detected with 1 cm−1 spectral and 0.5 μs time resolution over the 800–10 000 cm−1 range by time-resolved Fourier transform emission spectroscopy. The energy distribution of vibrationally excited NO2 durin…
The Krätschmer–Huffman carbon-arc method of preparing fullerenes has been used to generate carbon-coated transition metal (TM) and TM-carbide nanocrystallites. The magnetic nanocrystallites were extracted from the soot with a magnetic gradient field technique. For TM=Co the majority of nanocrystals exist as nominally…
The equilibrium properties of block copolymer liquids are studied using liquid state theory. We first present the formal extension of the polymer reference interaction site model theory to treat block copolymers of general architectures, and then apply this to the symmetric block copolymer using the Gaussian thread mo…
The frequency dependent first hyperpolarizabilities βvec(−2ω;ω,ω) (second harmonic generation) of conjugated molecules are studied using the time-dependent Hartree–Fock theory with the inclusion of solvent effects treated with the self-consistent reaction field theory. Using the intermediate neglect of differential ov…
M-type barium ferrite (BaFe12O19) films were deposited on a ZnO underlayer by sputtering with mixture of Ar, Xe, and O2 gases. PO2 and PAr+Xe were set at 0.01 and 0.09 Pa, respectively, where PXe was changed from 0.00 to 0.09 Pa. The dependencies of surface morphology, 〈D〉, Δθ50, Ms, and Hc⊥ and Hc∥ on PXe were invest…
The interpretation of various magnetization curves through Henkel plots and Δm plots has become popular in recent years for characterization of interactions in hysteresis. To investigate this approach, we have calculated Henkel plots using a hysteresis model based on independently moving domain walls. A variety of dem…
Ferrimagnetic Mn4N films have been successfully prepared at low process temperatures using the facing targets sputtering apparatus. The mixture gas of Ar and N2 with the ratio of N2 in pressure to total gas RN2 of 10% was optimal as the reactive working gas for depositing Mn4N films, since the deposition at excessive…
The unusual magnetic behavior of the 12k site in SrGaxFe12−xO19 (0.3≤x≤6.0) and SrInxFe12−xO19 (0.3≤x≤1.4) has been investigated by means of 57Fe Mössbauer spectroscopy at 298 K. The bifurcation of the 12k Mössbauer subspectrum into 12k1 and 12k2 components of widely differing intensities has been confirmed for both G…
By ball milling Sm2Fe17Nx the coercivity can be increased from 0.3 to 1.5 T. The coercivity increases continuously during milling up to a time of about 600 min, and then decreases for too intensive ball milling. This is connected to particle size reduction and other effects like the increase in oxygen content, introdu…
The high-frequency dielectric-constant tensor and the Born effective charge of ${\mathrm{TiO}}_{2}$ rutile are calculated using variational density-functional perturbation theory. The calculated structural properties and high-frequency dielectric constant show agreement with experiments at the level of a few percent.…
We have performed energy-band calculations of X 2 Mn 1- x V x Si (X=Fe and Co) at x =0, 0.25, 0.5, 0.75, 1.0. In ferromagnetic ordering, we obtain excellent agreement between calculated and experimental data for the magnetic moment per formula unit and the lattice constant, at each Mn content. We have obtained the res…
In this concise overview, the physical principles of magnetic Barkhausen effect will be briefly discussed and its recent applications in material characterization will be considered. There are new trends in micromagnetic Barkhausen effect emissions and its applications in the material characterization area. These emis…
Magnetic and microstructural investigations of some polycrystalline rare-earth—transition-metal (RE-TM) alloy thin films are reported. Emphasis was placed on pseudobinary alloys in the (TbxDy1−x)Fe2 and (TbxDy1−x)3Fe4 systems. The films were prepared by sputter deposition onto both room-temperature and high-temperatur…
Temperature-dependent magnetic properties of nine NdFeB sintered magnets with various Co-Nb, Co-V, or Co-Mo additions have been measured up to 175 °C using both closed-loop and open-circuit methods. The irreversible loss of induction, reversible temperature coefficient of induction (α), and temperature coefficient of…
We have carried out a quantitative low-energy electron-diffraction intensity analysis of the Ge(111) \ensuremath{\surd}3 \ifmmode\times\else\texttimes\fi{} \ensuremath{\surd}3 R30\ifmmode^\circ\else\textdegree\fi{}-Ag structure. It is found that the Ag atoms arrange according to a honeycomb chained trimer model (HCT)…
Quantitative measurements of the effects of pressure on the kinetics and quality of diamond films grown with hot-filament chemical-vapor deposition are reported. Pressure affects growth kinetics largely because it affects transport of precursors to the growing surface. H and CH3 concentrations at the growth surfaces a…
We report the valence-band and Co 2p photoemission spectra of ${\mathrm{LaCoO}}_{3}$ obtained at different temperatures (100, 300, and 573 K). Analysis of the core-level spectrum in terms of a configuration interaction model suggests that both low- and high-spin states coexist at the low temperature (100 K). It also i…