Materials Literature
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Loading a cantilevered bar allows studying the effect of a uniform, externally applied, and continuously variable strain field on the properties of surfaces. Straining a nominally flat Si(100) surface produces unequal populations of the 2 \ifmmode\times\else\texttimes\fi{} 1 and 1 \ifmmode\times\else\texttimes\fi{} 2…
A density-functional theory, based on the smoothed density approximation, is presented in order to study phase transitions in systems of hard spherocylinders with full translational and orientational degrees of freedom. We find both the nematic-isotropic and the $\mathrm{n}\mathrm{e}\mathrm{m}\mathrm{a}\mathrm{t}\math…
We present neutron-spin-echo data on the structural relaxation of glass-forming polybutadiene near the glass transition. Microscopic dynamics on the scale of an interchain distance and the monomeric friction coefficient derived from macroscopic viscosity relaxation obey the time-temperature superposition principle fol…
Weak features between 16000 and 19000 cm -1 in the absorption spectra of Cs 2 ReCl 6 and K 2 ReCl 6 are assigned as cooperative absorptions involving coupled excitations of the Gamma 8 ( 4 A 2g ) to Gamma 6 ( 2 T 1g ), Gamma 8 ( 2 T 1g ), Gamma 8 ( 2 E g ) transitions on neighbouring complex ions. The intensity mechan…
Many glasses and liquids exhibit a first sharp diffraction peak that is evidence for intermediate-range order caused by regularities in the packing of structural units. These tend to cluster around particular values of the wavevector when scaled by the nearest-neighbour distance or the mean inter-atomic spacing. The f…
Potassium titanyl orthophosphate KTiOPO 4 has been studied by Raman and infrared reflectivity spectroscopy in the range from a low temperature to room temperature and for various scattering configurations. The absence of a structural phase transition below room temperature is confirmed. The phonon modes are classified…
Magnetic measurement, are performed on R2Fe14–xCrxB compounds (R = Y, Nd, and Gd). These compounds, crystallize in the Nd2Fe14B structure up to x ≦ 3. The Curie temperature and the lattice constants a and c decrease with increasing Cr content. The spin-reorientation temperature in Nd2Fe14B is lowered when Cr replaces…
Samples of composition Nd15(Fe1−xCox)77B8 and La15(Fe1−xCox)77B8 were produced by arc melting and subjected to prolonged heat treatments. Metallographic analysis and x-ray diffraction revealed the presence of the magnetic La2(Fe1−xCox)14B phase in the La-based materials; lattice parameters for x=0–1 were determined. H…
Raman spectra of ZnS heavily doped with Al in the Stokes region of 400 to 500 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ show several distinct lines on the low-energy side of hexagonal-host modes. They are independent of temperature and thus attributed to Al-related local phonons. From vibrational-mode analysis and by…
The relative velocity ΔV(H)/V(H=0) and attenuation α(H) responses of 0.6 GHz Rayleigh-mode surface acoustic wave (SAW) pulses propagating through thin (<400 Å) films of nickel were measured as a function of in-film-plane dc magnetic bias field H. The films’ dc magnetoresistive response ΔR(H) was also measured.…
The thermal expansion and coefficient of linear thermal expansion of elbaite, schorl, and uvite specimens in the a and c directions have been determined from 80 K to room temperature with use of the standard strain-gauge technique. At room temperature it was found that for elbaite, ${\ensuremath{\alpha}}_{a}$=3.86\ifm…
Changes were measured in the resistivity and 1/f noise in polycrystalline Cu films due to defects induced by 500-keV to 1.1-MeV electron irradiation or 1-MeV ${\mathrm{Kr}}^{+}$-ion irradiation. Irradiation with 500-keV electrons increased the noise level in films maintained at 90 K by as much as an order of magnitude…
It has been previously shown that the building factor of three-phase transformer cores can be improved by using materials with different permeabilities for limbs and yokes. This paper presents results of a comprehensive experimental study of the effect of using conventional, high-permeability, and domain-refined grain…
It is known that a metastable crystalline thin-film structure can often be stabilized by choosing a suitable substrate. For single-crystal thin films, this pseudomorphic growth has been attributed to the stabilization of the metastable phase by epitaxial growth. However, in the polycrystalline structure, the mechanism…
Temperature dependence of the intrinsic coercivity (HcI ) of Pr17 (Fe0.9 Co0.1 )83−x Bx has been measured above room temperature and analyzed by expressing HcI as the difference between a term proportional to the anisotropy field (HA ) and a term corresponding to a local demagnetization field. The fraction in HA avail…
A combination of hydrogen decrepitation (HD) and jet milling (JM) has been used to produce powder for the processing of permanent magnets. The procedure has proved to be very successful for both NdFeB (Neomax) alloys and the NdDyFeNbB high coercivity alloys. The magnets produced by the HD/JM process showed excellent c…
Specific heat C of κ-(BEDT-TTF) 2 Cu(NCS) 2 was measured between T c (10.4 K) and 3 K. An anomaly around T c was observed. The specific heat data show unusual bending below T c in the C / T versus T 2 plot. At the lowest temperatures, C obeyed the T 3 law and no residual T -linear contribution was observed.
We report loss separation measurements performed on 1.8% SiFe nonoriented 0.2-mm laminations of variable grain size 20 μm≤s≤130 μm, in the frequency range 1 Hz≤ f≤300 Hz and peak induction range 0.7 T≤B≤1.5 T. It is shown that the excess loss behavior is well reproduced by the equation Pe =k(Bf)3/2, in agreement with…
Theoretical backscattering amplitude and phase functions, B(k) and \ensuremath{\varphi}(k), used in extended x-ray-absorption fine structure (EXAFS) studies show strong features in their k dependence which can be identified as a ``generalized Ramsauer-Townsend effect.'' This effect is studied in detail for elements wi…
We have studied the consequence of structure on the magnetic properties of 304 stainless steel in two distinct crystalline states. Ordinary 304 stainless steel has an fcc structure and is nonmagnetic at room temperature. By using a vapor quenching method, we have fabricated single-phase metastable bcc 304 stainless st…