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。
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…
We report the superconductivity with the onset temperature as high as 8 K in the organic conductor of β-(BEDT-TTF) 2 I 3 , bis-ethylenedithio otetrathiofulvalene-triiodide. The increased superconducting transition temperature was achieved by an application of a soft pressure, i.e. 1.3 kb. High value of the upper criti…
Present works describe the developments the low cost R-Fe-B sintered permanent magnets. Three different didymiums are chosen for the low cost mixtures of rare-earth elements. The studied alloy compositions are Fe-(32.5–34.5)wt. %R-(1–1.6)wt. %B, where R elements are didymium (Nd-10wt. %Pr), 5Ce-didymium (Nd-15%Pr-5%Ce…
The variation of lattice parameter, saturation magnetization, and Curie temperature on the addition of Ti4+, Zr4+, and Sn4+ to some Ni-Zn ferrite compositions are reported and the results are explained on the basis of the movement of the substituting ions first to the tetrahedral and finally to the octahedral sites of…
Measurements of recombination along the tracks of 2-MeV alpha particles and 0.7-MeV protons in thermally grown silicon dioxide are presented. The results agree quite well with the columnar recombination model at applied fields above about 1 MV/cm if one assumes an initial Gaussian column radius b=3.5 nm. The agreement…
Amorphous Tb-Fe thin films have been produced by dual-gun dc magnetron cosputtering, which allows a moderate range of compositions (spanning about 20 at. %) to be deposited in a single run under identical conditions. The films exhibit clean M-H loops and torque curves which are somewhat anomalous but show consistent t…
The phonon dispersion curves of the rutile-structure compounds ${\mathrm{GeO}}_{2}$, ${\mathrm{SnO}}_{2}$, ${\mathrm{NbO}}_{2}$, and ${\mathrm{VO}}_{2}$ have been calculated in the framework of a shell model which had been used previously to reproduce the measured dispersion curves of rutile (${\mathrm{TiO}}_{2}$) rat…
We describe detailed analyses of neutron powder diffraction data on Nd2Fe14B at several temperatures and discuss relationships between the crystal structure and the magnetic properties via comparison with other rare earth-transition metal systems, Nd2Fe17 in particular. Diffraction studies have also been performed on…
A model is presented which gives a unique magnetic-field-induced transition from a two-dimensional open-orbit metal to a semimetal. A magnetic field causes the open-orbit electron motion to become progressively more one dimensional, with an effective density of states proportional to H at low field. This leads to a Fe…
Commercial rare earth metals contain several atomic % oxygen, and intermetallics synthesized using these ingredients deviate markedly from the intended compositions. In this work, high purity rare earths (<20 ppm oxygen by weight) were used. Results for R2Fe14B systems with R = Y, Nd, Sm, or Gd have been previo…
A spin reorientation occurs in Nd2Fe14B starting around Ts= 150 K. We present data on tendencies in spin reorientations in systems (Nd1−xRx)2Fe14B and Nd2Fe14−xAxB where R=different rare earths and A=Co, Al. The insensitivity of Ts to some of these substitutions appears to indicate that Nd alone is responsible for the…