Materials Literature
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From data of initial magnetization isotherms, the magnetic entropy change ΔSM of the series of ferromagnetic perovskites La2/3(Ca1−xSrx)1/3MnO3, with x=0, 0.05, 0.15, 0.25, 0.50, 0.75 and 1, has been measured near their Curie temperatures. The results go from 3.7 J kg−1 K−1 for La2/3Ca1/3MnO3 to 1.5 J kg−1 K−1 for La2…
We performed an extensive first-principles study of nanowires in various pentagonal structures by using pseudopotential plane wave method within the density functional theory. Our results show that nanowires of different types of elements, such as alkali, simple, transition and noble metals and inert gas atoms, have a…
We present a Monte Carlo study of the surface anchoring of a nematic fluid on swollen layers of grafted liquid crystalline chain molecules. The liquid crystalline particles are modeled by soft repulsive ellipsoids, and the chains are made of the same particles. An appropriately modified version of the configurational…
Microscopic mechanisms of the puzzling insulating ferromagnetism of half-filled La$_{4}$Ba$_{2}$Cu$_{2}$O$_{10}$ are elucidated with energy-resolved Wannier states. The dominant magnetic coupling, revealed through evaluated parameters ($t$, $U$, and $J$), turns out to be the intersite direct exchange, a currently igno…
Magnetization measurements of molecular clusters [Mn12]2− with a spin ground state of S=10 show resonance tunneling at avoided energy level crossings. The observed oscillations of the tunnel probability as a function of the magnetic field applied along the hard anisotropy axis are due to topological quantum phase inte…
A liquid crystal lens with a simple cell structure is prepared using a hole-patterned electrode and an intermediate insulating layer. The focal length is variable and is a function of the applied voltage. With this new structure, it is possible to fabricate liquid crystal lenses of any size.
Using the highly precise full potential linearized augmented plane wave method, the phase stability, magnetism, and magnetostriction of Fe3Ga alloys were investigated. The magnetostrictive coefficients strongly depend on the atomic arrangement. The B2-like structure, although it is unstable in the small unit cell chos…
It was recently reported that the addition of nonmagnetic Ga increased the saturation magnetostriction (λ100) of Fe over tenfold while leaving the rhombohedral magnetostriction (λ111) almost unchanged. To determine the relationship between the magnetostriction and the magnetization we measured the temperature and stre…
Nanocrystalline (NC) ferrite powders have been synthesized using a 50 kW–3 MHz rf thermal plasma torch for high-frequency soft magnet applications. A mixed powder of Ni and Fe (Ni:Fe=1:2), a NiFe permalloy powder with additional Fe powder (Ni:Fe=1:2), and a NiFe permalloy powder (Ni:Fe=1:1) were used as precursors for…
Flexural Plate Wave (FPW) devices fabricated from Silicon Carbide (SiC) membranes are presented here which exhibit electrical and mechanical characteristics in its transfer functions that makes it very useful as a low voltage probe device capable of functioning in small areas that are commonly inaccessible to ordinary…
Half-metals are defined by an electronic structure, which shows conduction by charge carriers of one spin direction exclusively. Consequently, the spin polarization of the conduction electrons should be 100%. In reality this complete spin polarization is not always observed. Since the experimental search for half-meta…
The dielectric properties of MnxNi0.5−xZn0.5Fe2O4 ferrites with x varying from 0.05 to 0.4 synthesized by the citrate precursor method have been investigated as a function of frequency, temperature, composition, and sintering temperature. An increase in the dielectric constant is observed with the increase in Mn conce…
Abstract This paper provides a review of a systematic micro‐Raman scattering study on various lead‐ and barium‐based ABO 3 perovskites (A = Pb, La, Ba, Sr, Ce, Gd, Nd and B = Ti, Zr), Aurivillius‐type Bi‐layered compounds (SrBi 2 Ta 2 O 9 , Bi 4 Ti 3 O 12 ) and their solid solutions useful in a broad range of device a…
A range of Ni–Mn–Ga alloy compositions close to the stoichiometric Heusler composition, Ni2MnGa, has been reported to show field-induced strains of several percent. Such observations, and the magnitude of the strain observed, depend on the values of several critical material parameters, most importantly the martensiti…
The intercalation of large organic ammonium ions (tetramethylammonium ions (TMA + ), tetraethylammonium ions (TEA + ), tetrapropylammonium ions (TPA + ), and tetrabutylammonium ions (TBA + )) into layered graphite oxide (GO) was systematically investigated. The intercalation reactions were completed at 25 °C after 3 d…
A cobalt molecule that functions as a single-molecule magnet, [Co4(hmp)4(MeOH)4Cl4], where hmp− is the anion of hydroxymethylpyridine, is reported. The core of the molecule consists of four Co(II) cations and four hmp− oxygen atom ions at the corners of a cube. Variable-field and variable-temperature magnetization dat…
The increasing awareness of the need to create green and sustainable production processes in all fields of chemistry has stimulated materials scientists to search for innovative catalysts supports. These new catalytic supports should allow the heterogenization of most catalytic processes, increasing the efficiency and…
A broad classification scheme is proposed for half-metallic ferromagnets which embraces the possibilities of itinerant and localized electrons, as well as semimetallic and semiconducting electronic structure. Examples of each type are given. The problems of defining and measuring spin polarization are discussed and so…
A topological anomaly present at zero energy is shown to give rise to a peculiar and singular behavior of the dynamic and static conductivity in two-dimensional honeycomb lattices. A calculation in a self-consistent Born approximation reveals that this singular dependence prevails although being somewhat smoothed out…
Nanoparticles of LaF 3 doped with Ln 3+ (Ln = Eu, Er, Nd, and Ho) have been prepared that are dispersible in organic solvents. From the spectrum of Eu 3+ it has been concluded that the dopant ion occupies a La 3+ site. The luminescence decays are fitted biexponentially. A given possible explanation for this is a diffe…