Materials Literature
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Five absorption bands of the allowed 5d←4f transitions of Ce3+ were detected in the ultraviolet region between 37 and 51 × 103 cm-1 by σ- and π-polarized absorption, luminescence excitation, and MCD spectra with the single crystals of Ce3+ doped lanthanum ethylsulphate enneahydrate. In the crystal, Ce3+ is in a D 3h l…
A general theoretical treatment is developed for NMR spin-lattice (T 1 and T 1 rho ) and spin-spin (T 2 ) times for relaxation due to modulation for dipolar interactions by diffusion of atoms on inequivalent lattice sites. This extends previous calculations of T 2 to the other relaxation parameters and gives rate equa…
A model of the superionic conductor Ag 2 S is proposed and studies by the molecular dynamics technique using effective pair potentials. The self-diffusion for silver, D Ag (T), is in good agreement with experiment. The Ag density map and its temperature dependence is calculated. The authors also calculate the X-ray an…
The Raman spectra of the symmetric stretching v 1(A′1) mode of NO3 - ions have been measured in a series of molten nitrates, LiNO3, NaNO3, KNO3, RbNO3, CsNO3, AgNO3, TlNO3, at a temperature 10–20 K above each melting point. Temperature dependence of the Raman spectrum was also measured in molten NaNO3. Reorientation o…
The phase transformations and magnetic properties of single crystals of a MnAlC alloy are investigated. Using optical microscopy and X-ray diffraction method it is found that the morphology and the number of orientations of the τ-phases formed at 500 and 600 °C are different. This leads to a considerable difference i…
On the basis that metal films possess the properties of high reflection for infrared and induced transmission for visible bands, the authors have designed a broadband dichroic filter capable of transmitting visible and reflecting infrared bands through stacking to form a combined dielectric–metal–dielectric thin-film…
The hysteresis loops of three commercial magnets with room temperature energy products greater than 25 MGOe were obtained over the temperature range 4.2–700 K in applied magnetic fields extending to ±90 kOe. Two of the samples are of the Sm2Co17 type and the other of Nd2Fe14B. The magnetic parameters extracted from th…
Fe-Cr-Co ductile alloys produce magnetic properties comparable to those of Alnico permanent magnets family, up to (BH)max=91.2 kJ/m3(11.4 MGOe). It is technologically known that the addition of Ti to the Fe-Cr-Co alloys extends the α-phase region of system and improves the magnetic properties. The purpose of this work…
Magnetization and Mössbauer studies have been carried out on GdCo3B2 and DyCo3B2. These compounds are magnetically ordered with Curie temperatures of 56 and 21 K, respectively. The Co atoms are either nonmagnetic or carry a small moment in these compounds. The saturation moment of DyCo3B2 at 5 K is smaller than the Dy…
A setup is described to determine the flow alignment angle θ0 in nematic liquid crystals. Results for compounds with and without a strongly polar terminal cyano group indicate that the antiparallel dipole correlation associated with cyano groups has no influence on θ0. The influence of the occurence of a smectic-A pha…
The magnetic susceptibility of polycrystalline samples of Cs2CuCl4 has been measured over the temperature interval 1.1–30 K. A broad maximum in the data, centered around 2.6–2.7 K, is consistent with the existence of lower-dimensional antiferromagnetic interactions in this compound. The model used for fitting the data…
SmCo5, Sm2(Co,Fe,Zr)17, and (Sm+Ti)Fe amorphous films were deposited by rf sputtering onto water cooled substrates with an applied field, Hs, of 2.5 or 1.75 kOe in the plane of the substrates during the sputter deposition. All of these systems have been made so as to exhibit in-plane rectangular hysteresis loops when…
The behavior of the diffraction field of a Gaussian beam through an aperture depends on incidence conditions and aperture radius. The field spread in the Fraunhofer region varies with the curvature of the equiphase surface of the incident beam as well as the ratio of the aperture radius to the spot size. The divergenc…
A Mössbauer study of Fe3−xAlxO4 and Fe3−xGaxO4 has been undertaken. Measurements at low temperatures in magnetic fields enabled us to better separate the Fe(A) and Fe(B) subspectra and to determine the cation distribution on tetrahedral and octahedral sites. Whereas Al up to x=1.4 shows a strong preference for B sites…
Linear π diradicals are treated as a through-bond interaction of two radical centers. The ferromagnetic or antiferromagnetic electron coupling is examined by means of an analytic study of the interaction of two methylene groups (the radical centers) through a butadiene (the bridge). The interaction of each radical cen…
On sintered Nd-Fe-B permanent magnets, magnetic domain pattern changes in applied fields and at elevated temperatures were observed by the Kerr effect. Patterns on pole and side faces were recorded for different magnetization states in fields up to 17 kOe at 20 °C, and remanent patterns at temperatures up to TC. They…
Multiple-scattering theory is used to evaluate the effective dielectric function \ensuremath{\epsilon}(\ensuremath{\omega}) for disordered systems in which spherical inclusions are densely packed in a host medium. We compare the well-known quasicrystalline approximation (QCA) with Roth's effective-medium approximation…
Using high resolution transmission electron microscopy, morphological aspects of the polycrystalline silicon (polysilicon)-single crystal silicon interface have been correlated to the surface treatment used prior to polysilicon deposition, and to high-temperature annealing. Specimens which were chemically oxidized pri…
The origin of magnetic hardening has been examined in Fe-Nd-B magnets by correlating the magnetic properties with the microstructure and magnetic domain structure observed with electron microscopy. Hysteresis loops and susceptibility studies show a magnetic anomaly at around 140 K. Microstructure studies reveal the pr…
We demonstrate for the first time that Te87Ge8Sn5 films, which are amorphous as deposited, can be optically switched between the crystalline and amorphous states more than 106 times. The measured reflectivity changed from 40% to 60% and the transmission changed from 3% to 1.5%, respectively, between the amorphous and…