Materials Literature
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Complementary to the experimental studies on magic Ba clusters [Rayane et al., Phys. Rev. A 39, 6056 (1989)], it is theoretically found that magic Ba clusters with 13, 19, 23, 26, 29, and 32 atoms have icosahedral or polyicosahedral structures, which are induced by $5d$-electron bonding. As the cluster grows, the aver…
Ferroelectric/metal composites have been characterized for their electric field dependence of the dielectric and ferroelectric properties. The composites show an interesting change of dielectric properties with increasing metal concentration. A relatively high dielectric constant, up to four times as high as that of m…
Utilizing the containerless electrostatic levitation facility at NASA/MSFC, we were able to undercool the Ni59Nb41 (atomic) alloy by 210 K which was 160° farther than the results of previous flight experiments. Undercoolings were clustered around 200 K during the repeated melting–freezing cycles on a single sample. Pr…
SiO 2 / Ge:SiO 2 / SiO 2 sandwiched structure was fabricated for exploring efficient light emission. After annealed in N2 (O2<1%), this structure shows three photoluminescence (PL) bands at 293, 395, and 780 nm. The intensity of the 395 nm band is largely enhanced in comparison with that from the monolayered Ge…
Stress-free and two-way thermoelastic shape memory, with 1.2% strain and 6 K temperature hysteresis, has been found in single crystalline Ni52Mn24Ga24. The deformation can be enhanced more than three times, up to 4.0% shrinkage with a bias field 1.2 T applied along the measurement direction, or changed to 1.5% expansi…
By applying a transverse magnetic field ${B}_{\ensuremath{\perp}}$ of sufficient strength to the uniaxial molecular magnets ${\mathrm{Fe}}_{8}$ and ${\mathrm{Mn}}_{12}$, the tunneling splitting ${\ensuremath{\Delta}}_{t}$ of their $S\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}\ifmmode\pm\else\textpm\fi{}10$ mag…
The time-dependent relaxation of the remanent polarization in epitaxial lead zirconate titanate (PbZr0.2Ti0.8O3) ferroelectric thin films, containing a uniform two-dimensional grid of 90° domains (c axis in the plane of the film), is examined using piezoresponse microscopy. The 90° domain walls preferentially nucleate…
We show that the crystal growth rate of a very long-chain n-alkane C C(198)H(398) from solution can decrease with increasing supersaturation and follow strongly negative order kinetics. The experimental behavior can be well represented by a theoretical model which allows the molecule to attach and detach as either ext…
We report an investigation of the heterogeneity in supercooled liquids and glasses using the non-Gaussianity parameter. We simulate selenium and a binary Lennard-Jones system by molecular dynamics. In the non-Gaussianity three time domains can be distinguished: an increase on the ps scale due to the vibrational (balli…
Monoclinic zirconia samples were irradiated with 300 MeV Ge and Ni ions at increasing ion fluences. Their structural evolution was monitored in situ by x-ray diffraction and ex situ by Raman spectroscopy. No amorphization of zirconia was observed in both cases. However, a transition from the monoclinic to the tetragon…
We present elastic and quasielastic neutron scattering measurements characterizing peculiar short-range charge-orbital and spin order in the layered perovskite material La1.5Sr0.5CoO4. We find that below T(c) approximately 750 K holes introduced by Sr doping lose mobility and enter a statically ordered charge glass ph…
The size distribution, band gap energy, and photoluminescence of silicon nanocrystals embedded in SiO2 have been measured by direct and independent methods. The size distribution is measured by coupling high-resolution and conventional electron microscopy in special imaging conditions. The band gap is calculated from…
Epitaxial BaTiO3(111)/SrTiO3(111) multilayered thin films have been investigated with various periods of stacking layer between 0.45/0.45 and 10/10 nm on Nb-doped SrTiO3(111) substrates by a pulsed-laser deposition technique. Upon decreasing the period of each layer, the spacing of (111) plane (d111) of the multilayer…
We present a molecular dynamics study of the single-particle dynamics of supercooled water confined in a silica pore. Two dynamical regimes are found. Close to the hydrophilic substrate molecules are below the mode coupling crossover temperature, T(C), already at ambient temperature. The water closer to the center of…
Contents: 5.1 Introduction 5.2 Concepts and definitions 5.3 The tight-binding picture of bonding 5.4 Adsorption of isolated adatoms 5.5 Alkali-metal adsorption: the traditional picture of on-surface adsorption 5.6 Substitutional adsorption and formation of surface alloys 5.7 Adsorption of CO on transition-metal surfac…
We have measured and calculated the magnetocaloric effect in macroscopic samples of oriented high-spin molecular clusters like Mn12 and Fe8 as a function of the temperature and both the intensity and the sweeping rate of the applied magnetic field. We have observed a high magnetic entropy variation around the blocking…
It is shown that a pulsed current driven through Ni nanowires provokes an irreversible magnetization reversal at a field distant from the spontaneous switching field $H_{sw}$ by $ΔH$ of as much as 40 % of $H_{sw}$. The state of the magnetization is assessed by magnetoresistive measurements carried out on single, isola…
The study deals with the Payne effect (a substantial decrease in the storage modulus of a particle-reinforced elastomer with an increase in the amplitude of mechanical oscillations). The influence of temperature, concentration of filler and amplitude and frequency of strains is analyzed on the mechanical response of f…
The thermoelectric power (TEP) of single-walled carbon nanotubes (SWNTs) is extremely sensitive to gas exposure history. Samples exposed to air or oxygen have an always positive TEP, suggestive of holelike carriers. However, at fixed temperature the TEP crosses zero and becomes progressively more negative as the SWNTs…
20 mm long ropes consisting of soundly aligned single-walled carbon nanotube (SWNT) ropes, synthesized by the catalytic decomposition of hydrocarbons, were employed for direct tensile strength measurements. The average tensile strength of SWNT rope composites is as high as 3.6±0.4 GPa, similar to that of carbon fibers…