Materials Literature
按标题、摘要、年份、主题和来源检索公开元数据。结果保留作者、摘要、分类与原始来源链接。
Linear π diradicals are treated as a through-bond interaction of two radical centers. The ferromagnetic or antiferromagnetic electron coupling is examined by means of an analytic study of the interaction of two methylene groups (the radical centers) through a butadiene (the bridge). The interaction of each radical cen…
On sintered Nd-Fe-B permanent magnets, magnetic domain pattern changes in applied fields and at elevated temperatures were observed by the Kerr effect. Patterns on pole and side faces were recorded for different magnetization states in fields up to 17 kOe at 20 °C, and remanent patterns at temperatures up to TC. They…
Multiple-scattering theory is used to evaluate the effective dielectric function \ensuremath{\epsilon}(\ensuremath{\omega}) for disordered systems in which spherical inclusions are densely packed in a host medium. We compare the well-known quasicrystalline approximation (QCA) with Roth's effective-medium approximation…
Using high resolution transmission electron microscopy, morphological aspects of the polycrystalline silicon (polysilicon)-single crystal silicon interface have been correlated to the surface treatment used prior to polysilicon deposition, and to high-temperature annealing. Specimens which were chemically oxidized pri…
The origin of magnetic hardening has been examined in Fe-Nd-B magnets by correlating the magnetic properties with the microstructure and magnetic domain structure observed with electron microscopy. Hysteresis loops and susceptibility studies show a magnetic anomaly at around 140 K. Microstructure studies reveal the pr…
We demonstrate for the first time that Te87Ge8Sn5 films, which are amorphous as deposited, can be optically switched between the crystalline and amorphous states more than 106 times. The measured reflectivity changed from 40% to 60% and the transmission changed from 3% to 1.5%, respectively, between the amorphous and…
We have used both electron-induced soft x-ray emission and fast inelastic electron scattering to observe 1S core-level emission and absorption in graphite near threshold. Linear phonon coupling with partial relaxation is found to quantitatively explain the absorption linewidth, the emission broadening, and the unusual…
GdRh, a ferromagnetic intermetallic, is of interest as a working material for magnetic refrigeration. The requirements for such materials have been discussed by Barclay et al. and it is in this context that we analyze our data. Magnetic measurements of Buschow et al. have indicated TC =24 K while specific heat measure…
Abstract Die synthetisierten farbigen α‐Styrylpyrylium‐Salze 2, 4 und 6 werden größtenteils im kristallinen Zustand zu den farblosen Cyclobutanen 7, 8 und 9 photodimerisiert (inverse Photochromie), deren r‐ctt ‐Konfiguration nachgewiesen wird. Bestrahlung von 2h in Lösung erzeugt u. a. das unerwartete Bispyrylium‐Salz…
Cooperative effects during both alkali-Ca and Na-K migration under electron irradiation of glasses have been pointed out for the first time by analysis of experimental data in the framework of the thermodynamics of irreversible processes.
MnAlGe is a ferromagnet with a unique crystal structure including two-dimensional arrays of Mn atoms in it. In order to find the magnetic properties characteristic of this structure, magnetic and electric measurements were made for Mn0.9M0.1AlGe (M:Mn, Cr, Fe) and MnGaGe. It has been found that the susceptibility abov…
We have determined the frequency-dependent scrE\ensuremath{\rightarrow}\ensuremath{\perp}c\ensuremath{\rightarrow} dielectric function \ensuremath{\epsilon}(\ensuremath{\omega}) for the stage-1 graphite intercalation compounds ${\mathrm{KC}}_{8}$, ${\mathrm{LiC}}_{6}$, and ${\mathrm{KHgC}}_{4}$ in the range 0--40 eV,…
A Hall coefficient and an electrical conductivity of NbO 2 were measured just below the metal-insulator transition temperature. It is concluded that the conduction is mainly a band conduction of large polarons above 550 K with an energy gap decreasing to zero toward the transition. A reflectivity measurement was consi…
Silver-based high-reflectance coatings that can withstand the humid and polluted conditions common in the open air have been developed for astronomical telescope optics. The successful designs incorporate a silver reflective layer with a copper underlayer and a stack of dielectric overlayers. Prototypes have been depo…
On clean and Ni-contaminated surfaces of Si(110), experiments of low-energy electron diffraction (LEED) and Auger-electron spectroscopy (AES) were carried out under various heat treatments. The Si(110) clean surface has a ``16\ifmmode\times\else\texttimes\fi{}2'' structure and it transforms reversibly to 1\ifmmode\tim…
The reaction of Si (100) with C2H4 from a molecular beam source has been studied using x-ray photoelectron spectroscopy, electron-energy-loss spectroscopy, and Auger spectroscopy. Using these methods, we have studied the kinetics of SiC formation under conditions where no gas-phase excitation processes can contribute.…
Particle size effects on magnetic properties of BaFe12−2xTixCoxO19 fine particles were investigated. Saturation magnetization of these particles decreased with decreasing particle size. This result can be explained with the existence of a nonmagnetic thin layer, several angstroms in thickness, on the surface of the pa…
A whole new class of high-performance permanent magnet materials is based on the ternary tetragonal structure R2Fe14B, where R is one of the rare-earth elements. We have successfully grown single crystals of this structure with R=Y, Nd, and Tb. Y is a nonmagnetic rare-earth substitute, while Nd and Tb couple ferro- an…
Outstanding permanent magnet properties were recently observed in a Nd-Fe-B compound which was shown to crystallize in a new phase, R2Fe14B. Polarized neutron measurements are reported on Y2Fe14B and Nd2Fe14B single crystals. The 3d Fe moment on different sites in Y2Fe14B at 4.2 K is closely related to local environme…
Photoelectron spectroscopic measurements of core-electron levels in cations of transition-series insulators commonly show ``satellite'' features in the vicinity of the ``main'' photoelectron peaks. In this paper, the relationship between main lines and adjacent satellites is systematically examined for 3d-series insul…