Materials Literature
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High isotropic remanences and energy products have been obtained in melt-spun Nd-Fe-B samples with a fine grained mixture of α-Fe and Nd2Fe14B1 containing more than 50 wt % of α-Fe. Reduced remanences as high as 0.78 with high saturation magnetization (190 emu/g) led to (BH)max of 14 MGOe. The coercivities varied from…
In this paper we report on Schottky barrier height measurements of nickel on both diamond (111) and (100) surfaces, as a function of surface preparation. The Schottky barriers of thin (5 \AA{}) nickel films on natural type-IIb (p-type semiconducting) diamond (111) and (100) surfaces were determined with ultraviolet ph…
Using rapid thermal processing (RTP) we recently demonstrated the production of high quality well ordered barium ferrite films in times much shorter than those required by a conventional annealing process. Influence over the magnetic and structural properties developed in annealed samples was also achieved by variatio…
The influence of Si, Co, and Dy2O3 on magnetic properties of sintered 40Cedidymium–Fe–B magnets was investigated and related to the microstructure through transmission electron microscopy (TEM) investigations. It is found that the decrease in iHc and Tc caused by the presence of Ce in the 40Cedidymium could partly be…
The magnetic and structural properties of mechanically alloyed Nd2Fe14B+ (Fe, FeCo) powders have been investigated over a wide range of temperatures. X-ray diffraction patterns on samples milled for 48 h showed that the powders had a two-phase structure consisting of a disordered Nd-Fe-B alloy and α-Fe with a fine gra…
The current-voltage characteristic of polycrystalline titanium-substituted lithium ferrites has been measured at temperatures above room temperature. At voltages below a critical value an Ohmic relationship is observed, while it obeys a power-law relationship (i∝Vα, where α is a temperature-dependent constant) above t…
We report x-ray-absorption spectra at the oxygen K edge for ${\mathrm{LaNi}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$${\mathit{M}}_{\mathit{x}}$${\mathrm{O}}_{3}$ (M=Mn, Fe, and Co) for values of x spanning the entire composition range which exhibit metal-insulator transitions at critical values of x. This study clearly…
Co-Sn substituted barium ferrite particles, BaFe12−2xCoxSnxO19 (0≤x≤1.4), have been investigated using x-ray, VSM, and Mössbauer spectroscopy. The magnetocrystalline-anisotropy constant has been determined as a function of x from an analysis of the approach to magnetic saturation. Mössbauer spectra indicate that Co2+…
We have studied the origin of the visible photoluminescence (PL) from oxidized porous Si fabricated by rapid-thermal-oxidization processes. At low oxidation temperature (${\mathit{T}}_{\mathrm{ox}}$), the PL spectrum with a peak near 750 nm is observed, and silicon oxyhydrides and silicon oxides are formed at the surf…
Ba-ferrite is an attractive candidate for future high-density recording media because of its large coercivity, corrosion resistance, high hardness, and durability. In contrast to most recent work on Ba-ferrite thin film media, polycrystalline films with large in-plane remanence for longitudinal recording are emphasize…
Effective quadratic nonlinearities as high as 0.2 pm/V are reported for the first time to our knowledge in poled germanosilicate fibers. This value is ~200 times higher than previously achieved in these fibers. The presence of Ge is found to enhance the efficacy of both thermal (in combination with OH doping) and elec…
The magnetic characteristics of high-anisotropy Sm(Co1−xCux)5 phases are determined experimentally at 300 K in the range x<0.6. The saturation magnetization Ms decreases and vanishes for SmCo2Cu3. Identical behaviors of Ms and Curie temperature TC versus x are observed in the range x<0.6. For significant…
The geometrical structure of small nickel clusters is probed via molecular adsorption of nitrogen on their surfaces. Nitrogen uptake patterns can be rationalized with the proposed structures if it is assumed that N2 binds to every exposed nickel atom, that the binding energies decrease with increasing metal—metal coor…
Femtosecond photon-echo techniques are used to probe the dynamics of quantum-confined excitons in nanocrystals of CdSe. Using three-pulse photon echoes, the modulation of the echo signal from the LO-phonon mode is effectively suppressed, and both the electronic dephasing and the couplings to lattice vibrations are pro…
The microwave absorbing characteristics and resonance of Y-type hexagonal ferrite–rubber composites were investigated. The complex permeability and permittivity of Ni2−xZnxY ferrite bodies were measured using a network analyzer in the frequency range of 200 MHz–14 GHz. Two types of resonance, the domain wall and the s…
Recently it was discovered that composites of Terfenol-D alloys with an insulating binder produce very large magnetostrictions. Resistivities of these composites reach high values, making them attractive for high-frequency applications which require small eddy current losses. In this paper the magnetostriction, magnet…
We present ab initio quantum-mechanical molecular-dynamics simulations of the liquid-metal--amorphous-semiconductor transition in Ge. Our simulations are based on (a) finite-temperature density-functional theory of the one-electron states, (b) exact energy minimization and hence calculation of the exact Hellmann-Feynm…
Field emission from two special kinds of emitters has been studied in detail: intentionally introduced particles of controlled geometry, and sites produced by intentional mechanical damage to the cathode surface. We found that the size of particles seems to play no role in their threshold field but their shapes are a…
A simple but generalized, ballistic collisional based, model of densification and stress evolution in ion-assisted deposition of thin films is developed. It is proposed that densification of voided films occurs by forward atomic recoil generation and, consequentially, modification of tensile stresses. The total recoil…
Because they are cheap and available in very large quantities as a waste material from palm oil mills, oil palm empty fruit bunches can be seen as a potentially valuable starting material for manufacturing solid carbon products, which are widely used in the field of electrical engineering. In this context it was there…