Materials Literature
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Time dependence of magnetization in ferromagnetic materials was first described towards the end of the 19th century. Subsequently, two types of mechanisms responsible for time dependent behavior were identified and became known as ‘‘diffusion’’ and ‘‘fluctuation’’ after-effect or viscosity. The former depends on therm…
Spherical and monodisperse Co20Ni80 particles were prepared, in the micrometer and submicrometer size range, by the polyol process. X-ray diffraction showed crystalline particles with a fcc structure. From electron probe microanalysis a fairly homogeneous distribution of both elements within each particle was observed…
We have studied the crystallization, crystal structure, microstructure and magnetic properties of R-Fe-B (R=Nd,Pr,Dy,Tb) based melt-spun ribbons consisting of a mixture of R2Fe14B and α-Fe phases. All the samples crystallize first to α-Fe and a metastable phase (Y3Fe62B14 for R=Nd,Pr,Dy and TbCu7 for R=Tb) before they…
Changes in the impedance, ≊600%/Oe, at axial fields less than 1 Oe have been observed in the presence of a 90 kHz, few mA current through a soft, nearly zero magnetostrictive wire. In this 125 μm diameter CoFeSiB amorphous wire we observe a total change of 160% at the maxima of the impedance in dc fields less than 2 O…
Conflicting reports of large magnetoresistive and magnetoinductive effects in amorphous FeCoSiB wires and ribbons prompted the impedance measurements reported here. The spectra (0≤f≤3.2 MHz) were obtained at room temperature using a commercial impedance analyzer both as functions of axial magnetic field (−140<H…
Stabilizing the 1-12 phase with cerium was possible using a special heat treatment. The structural and magnetic properties of Ce(Fe,M)12 and their nitrides, for M=Ti, V, Cr, Mo, etc., were investigated using x-ray-diffraction and magnetic measurements. The effects of interstitial nitrogen atoms on lattice parameters,…
Sintered magnets were prepared from jet-milled and hydrogen-decrepitated jet-milled Nd-Fe-B:(Cu,Nb) powder. The HD process started after heating the cast material up to 200 °C. A single-step annealing treatment at 525 °C improved the magnetic properties of all samples. Magnets prepared from the jet-milled powder requi…
Ferrimagnetic Mn4N films were deposited on Si (100) substrate by dc reactive magnetron sputtering from sintered Mn target. Highly (002) textured Mn4N ordered phase is formed in situ at studied substrate temperatures of 150–250 °C without further annealing. Anomalous perpendicular magnetoanisotropy exists in these face…
We have made time-of-flight neutron diffraction measurements on α-manganese metal. Powder diffraction measurements were made at 14 temperatures between 15 and 305 K, and single crystal measurements were made at 15 and 300 K. We found that the crystal structure of α-Mn is tetragonal below its Néel point of 100 K, with…
Abstract Sorption and transport properties of water through films of Nylon‐6 were obtained at 5, 23, and 40°C. Commercially available films were used and a Cahn electrobalance was employed for measuring the water uptake by the polymer samples. Values of the water sorption isotherms are accurately described by the Lang…
As an attempt to establish a unified treatise of the structure of amorphous germanium, silicon, and (tetrahedral) carbon, a series of reverse Monte Carlo simulations were carried out for all of the three materials. A number of constraints have been applied during the calculations in order to test how many (and how muc…
We have used the empirical pseudopotential method to study the electronic and optical properties of [001] Si quantum wires with (110)--(1\ifmmode\bar\else\textasciimacron\fi{}10) square cross sections ranging from 4\ifmmode\times\else\texttimes\fi{}4 to 14\ifmmode\times\else\texttimes\fi{}14 monolayers (7.7\ifmmode\ti…
Cobalt particles were prepared with the microemulsion method in the binary system of DDAB (didodecyldimethylammonium bromide)/toluene by reduction of CoCl2 with NaBH4. The average particle size of the as-prepared samples could be varied from 1.8 to 4.4 nm by controlling the concentration of CoCl2 in the solution of DD…
Amorphous magnetostrictive films of the binary compound SmxFe1−x as well as of the ternary compound (TbyDy1−y)xFe1−x were prepared by rf or dc magnetron sputtering using either a multitarget arrangement with pure element targets or cast composite-type targets. The magnetostrictive properties of (Tb0.3Dy0.7)0.4Fe0.6 an…
The self-assembled network of conducting polyaniline (PANI), protonated by camphor sulfonic acid (CSA), in a matrix of insulating polymethylmethacrylate (PMMA) has a remarkably low percolation threshold. The critical volume fraction (f) of the PANI-CSA phase segregated in PMMA is inferred from the concentration depend…
In order to determine the value of the intrinsic magnetic moment of the α ″ phase, the films of nitrogen-martensite with various N content were fabricated under various reactive sputtering conditions. The magnetic moment of (α ″+α′)-Fe16N2 films is discussed in connection with the change of the unit-cell volume of the…
Raman spectra of purified carbon deposits containing multishelled carbon nanotubes of average diameter 10--12 nm show narrow vibrational bands and no phonon softening in contrast to unpurified material. This is in agreement with lattice-dynamical calculations using a semiempirical pseudopotential, which predicts no si…
Luminescence excitation spectra are employed to study the electronic states of CdSe nanocrystals ranging in size from 9 to 26 Å radius at 77 K. These studies show that all samples have, in addition to the discrete manifold of quantum confined electronic excitations, a threshold for continuum absorption. Absorption int…
Micromagnetic calculations are used to investigate coercivity and energy products of magnets consisting of an aligned hard-magnetic skeleton phase and a soft-magnetic phase with high saturation magnetization. Compared to the present-day theoretical limit of 516 kJ/m3 for single-phase Nd2Fe14B, the energy product in su…
Nb-doped SrTiO3 (STO) thin films (Nb, 0<x<100 mol%) with a-axis orientation have been prepared on nondoped STO (100) and LaAlO3 (100) single crystals using a pulsed laser deposition technique. Solid-solution films are formed between STO and SrNbO3 without any impurity phases. Electrical conductivities of…