Materials Literature
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The time-dependent properties of arrays of elongated and mutually aligned iron particles in alumite (anodized aluminum oxide film) have been studied. At a constant particle diameter of 11 nm, the magnetic viscosity is nearly independent of the particle length (varied from 140 to 440 nm). The activation volume (1.1 to…
We report on surface structure analyses by quantitative low-energy electron diffraction for ultrathin films of 1.5 and 5 ML Co on Cu(111) and on the structural changes they undergo when additionally covered by 2--3 ML copper. The thin cobalt film is dominated by continuation of the fcc stacking dictated by the substra…
A simplified theory of magnetostriction, derived from micromagnetics, is presented. The theory is designed to provide a systematic, yet manageable, quantitative tool in the design of magnetostrictive actuators, by making the “calculation” of the overall response of magnetostrictive specimens subjected to applied magne…
A thin amorphous Ba–Fe–O film was deposited as an underlayer for the growth of c-axis oriented hexagonal barium ferrite (BaM) films using a facing targets sputtering system. This underlayer facilitates the crystallization and improves the crystallinity for hexagonal M phase. BaM films with c-axis orientation can be pr…
Charge transport in polyaniline protonated fully with methane sulphonic acid (MSA) and polyaniline (MSA)-polyurethane [PANI(MSA)-PU] blend has been investigated through measurements of temperature (T) and electric field (E) dependence of conductivity (\ensuremath{\sigma}), temperature dependence of thermoelectric powe…
Double-exchange ferromagnets with their associated large magnetoresistance have recently been considered as candidates in magnetic storage applications. We review materials aspects of one compound family, La1−xCaxMnO3. There exist two distinct low temperature regimes; (i) ferromagnetic and metallic (x<0.5) and…
Active powders of Ni–Zn ferrite were synthesized by soft chemical approaches and were extensively characterized using x-ray diffraction, scanning electron micrographs, vibrating sample magnetometer, resistivity, and permeability/loss factor techniques. The variation in the sintering conditions established a useful mic…
Light-induced anchoring of the molecular director is reported to be an efficient method for writing permanent holographic gratings in dye-doped liquid crystals. We have achieved higher sensitivity and spatial resolution in these materials with other methods. An energy density as low as 10(-1) J/cm(2) was sufficient to…
We have deposited epitaxial diamond films with very low angular spread on epitaxial β-phase silicon carbide layers on silicon (001) substrates. From x-ray rocking curve measurements, half-widths of the angular spread of the crystal orientation as low as 0.6° have been determined, which is the smallest value ever repor…
A three-dimensional (3D) rewritable optical memory using photochromic material is described for high-density memory. The bits are recorded in a 3D volume of photochromic material. A transformation of the photochromic molecule between two isomers with different absorption spectra can be stimulated by irradiation with a…
The multilayer thin films having the form of Ti(30 nm)/Fe(dFe)/[Nd–Fe–B(dNd–Fe–B)/Fe(dFe)] ×5/Ti(30 nm)/glass were fabricated on glass substrates by means of radio frequency (rf) sputtering, with dFe varied from 0 to 50 nm and dNd–Fe–B from 0 to 100 nm. Magnetization measurements have revealed that the minor loops of…
In this work polycrystalline perovskite with composition La0.7Ca0.3Fe0.05Mn0.95O3 has been produced by standard ceramic method. A considerable change occurs in magnetic, transport and magnetoresistance properties with respect to the classic composition without Fe. The introduction of a different metal, Fe, in Mn-O lay…
A thorough study of the Mössbauer spectra (MS) of a lightly iron doped (2%) polycrystalline La0.75Ca0.25MnO3 compound has been carried out from T=4.2 K up to 300 K. The MS for T>Tc and at T=4.2 K show one component. The corresponding hyperfine parameters are compatible with S=5/2 Fe3+ in octahedral coordination…
We present angle-resolved photoelectron spectra and surface state dispersions for the clean, 2\ifmmode\times\else\texttimes\fi{}1 reconstructed (111) and (100) surfaces of diamond. For the (100) surface a surface state is found in the gap of the projected bulk band structure around Y-bar, which has a binding energy of…
We present a theoretical study of the magnetic polaron associated with an electron-hole pair in a diluted magnetic semiconductor quantum dot. It is based on the effective-mass approximation in the strong confinement regime, which incorporates the coupling between the light- and heavy-hole bands. The magnetic polaron,…
We report on the metal-insulator transition of La0.5Sr0.5CoO3 thin films deposited by pulsed laser ablation on LaAlO3 substrates. The films were cooled in oxygen partial pressures between 760 and 10−5 Torr and electrical resistivity of the films was measured as a function of cooling oxygen pressure. La0.5Sr0.5CoO3 fil…
The results of low-temperature, ultrahigh-resolution ultraviolet photoemission studies of the electronic structure of stable icosahedral ${\mathrm{Al}}_{65}$${\mathrm{Cu}}_{20}$${\mathrm{Fe}}_{15}$, ${\mathrm{Al}}_{64}$${\mathrm{Cu}}_{24}$${\mathrm{Fe}}_{12}$, ${\mathrm{Al}}_{65}$${\mathrm{Cu}}_{20}$${\mathrm{Ru}}_{15…
Charge-ordered stripes in La1−xCaxMnO3 with x>0.5 were studied by electron diffraction and electron microscopy. Charge-ordered domains were observed in dark-field images and the stripes within the domain were revealed by high resolution lattice images. The modulation wave vector δ of the charge ordering follows…
Lifetimes of hot electrons in the 1.3--3.2-eV energy range at low index surfaces of Cu((100),(110),(111)) are measured by two-photon time-resolved photoemission spectroscopy with 10 fs resolution. Energy dependence of the lifetimes deviates from the (E-${\mathrm{E}}_{\mathrm{F}}$${)}^{\mathrm{\ensuremath{-}}2}$ functi…
The determination of the magnetic properties of antiferromagnetic Cr alloys requires careful consideration of the influence of the applied magnetic field. In this work we show that alloys of Cr-x at. % V present a Curie–Weiss paramagnetism above the Néel temperature, which is suppressed by a characteristic field HL. S…