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The carrier dynamics of amorphous [Ge.sub.2][Sb.sub.2][Te.sub.5] films are studied by using the femtosecond pump-probe technique. The change in reflectivity is a type of switching phenomena that can be controlled by electron effects and the temporal response properties of amorphous [Ge.sub.2][Sb.sub.2][Te.sub.5] films on the picosecond time scale is used for ultrafast optoelectric switching applications.

Langmuir-Blodgett films of tetra-neopentoxy phthalocyanine zinc (TNPPcZn) were prepared. Static optical recording behavior was tested in the Langmuir-Blodgett films of TNPPcZn. The reflectivity contrast was more than 100% in a writing and erasing cycle experiment. This is the first time to our knowledge that writing and erasing experimental data have been obtained in TNPPcZn film.

Longitudinal optical phonon modes in a ZnSe-ZnTe strained layer superlattice were investigated. The results showed that the red shifts of phonon frequencies were brought about by confinement and elastic strains. Tensile strain in the ZnSe layer induced red shifts while compressive strain induced blue shifts.

A new study uses the single-beam Z-scan technique to measure the nonlinear absorption and refraction properties of CdTr microcrystals doped in borosilicate glass.

Time-resolved reflectivity measurements are used for studying the fast phase transition processes on [Ge.sub.2][Sb.sub.2][Te.sub.5] film induced by picosecond laser pulses. The studies have shown that after picosecond laser pulse priming, reversible switching has occurred upon picosecond laser pulse irradiation with the same well-chosen fluence.

The near-field optical distribution and properties of Sb thin film thermal lens are calculated and stimulated using the finite-difference-time-domain method. The results show that within the near-field distance to the output plane of thermal lens, the spot size is approximately 100 nm, and its intensity is greatly enhanced, which is higher than that of incident light.

Presents a study that investigated the characteristic triangular cross-grid dislocation structure in sapphire single crystals by means of x-ray transmission topography. Characteristics of sapphire; Description of typical x-ray topographs; Function of x-ray topography in the determination of Burgers vector.

Discusses the measurement by Z-scan technique of third-order optical nonlinear susceptibilities of Bi2O3 nanoparticles coated by a layer of stearic acid in toluene sol and bare in hydrosol. Determination of the figures of merit related to linear loss and two-photon absorption; Suitability in all-optical switching applications.

In order to obtain a super-resolution non-diffraction beam, we propose a fast searching method to design a ternary optical element combined with the circularly polarized light. The optimized results show that a beam with a spot size of 0:356λ and depth of focus of 8:28λ can be achieved by focusing with an oil lens of numerical aperture NA = 1:4 and refractive index of oil n = 1:5. The analysis reveals that the spot size of transverse component is 0:273λ, indicating that the super-resolution effect mainly comes from the transverse component. The spot size inside the media can theoretically reach down to 0:273λ because the spot size inside the media is mainly determined by the transverse component. [ABSTRACT FROM AUTHOR]

Based on study of non-isothermal crystallization kinetics and orthogonal test of pulsed-laser crystallization parameters of Ge1Sb4Te7, minimum nanosecond laser pulse duration (threshold) for crystallization recording was used for optical –electrical hybrid operation. The crystallized bits arrays were optically recorded with minimum pulse duration of 40 ns and electrically read out with maximum current signal contrast of ∼20 times. [ABSTRACT FROM AUTHOR]

Four novel metal(II) complexes, Ni(L)2, Co(L)2, Cu(L)2, and Zn(L)2 (L = 5-(2-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)hydrazono)-1,3-diethyl-2-thioxo-dihydropyrimidine-4,6(1H,5H)-dione), were synthesized using the procedure of diazotization, coupling and metallization. Their structures were identified by elemental analyses, 1H NMR, ESI-MS and FT-IR spectra. The effect of different central metal(II) ions on absorption bands of the metal(II) complexes was researched. The thermal properties of the metal(II) complexes were investigated by thermogravimetry (TG) and differential scanning calorimetry (DSC). Furthermore, the thermodynamic parameters, such as activation energy ( E*), enthalpy (∆ H*), entropy (∆ S*) and free energy of the decomposition (∆ G*) are calculated from the TG curves applying Coats–Redfern method. The results show that the metal(II) complexes have suitable electronic absorption spectra with blue-violet light absorption at about 350–450 nm, high thermal stability with sharp thermal decomposition thresholds. [ABSTRACT FROM AUTHOR]

The dependence of thermal properties of Ag8In14Sb55Te23 phase-change memory materials in crystalline and amorphous states on temperature was measured and analyzed. The results show that in the crystalline state, the thermal properties monotonically decrease with the temperature and present obvious crystalline semiconductor characteristics. The heat capacity, thermal diffusivity, and thermal conductivity decrease from 0.35 J/g K, 1.85 mm2/s, and 4.0 W/m K at 300 K to 0.025 J/g K, 1.475 mm2/s, and 0.25 W/m K at 600 K, respectively. In the amorphous state, while the dependence of thermal properties on temperature does not present significant changes, the materials retain the glass-like thermal characteristics. Within the temperature range from 320 K to 440 K, the heat capacity fluctuates between 0.27 J/g K and 0.075 J/g K, the thermal diffusivity basically maintains at 0.525 mm2/s, and the thermal conductivity decreases from 1.02 W/m K at 320 K to 0.2 W/m K at 440 K. Whether in the crystalline or amorphous state, Ag8In14Sb55Te23 are more thermally active than Ge2Sb2Te5, that is, the Ag8In14Sb55Te23 composites bear stronger thermal conduction and diffusion than the Ge2Sb2Te5 phase-change memory materials. [ABSTRACT FROM AUTHOR]

Discusses the transition from in-plane to perpendicular magnetization in GdFeCo/AlN/TbFeCo magnetostatic coupling films. Determination of the molybdenum layer composition by fluorescence X-ray analysis; Preparation of the magnetostatic coupling films (GdFeCo/AlN/TbFeCo) used for center aperture detection disk by sputtering; Finding that the magnetization direction of readout layer changes from in-plane to perpendicular with increasing temperature.

Dicusses the measurement of the spectroscopic properties of Yb3+dope niobosilicate glasses. Systematic variations in the spectroscopic properties; Advantages of glass host over laser glasses; Comparison of properties.

Using first-principles simulations, we propose a simple mechanism and an easy-controlled method for reversible modification of supported nanoclusters on surfaces with atomic precision. As illustrated, individual atoms at edges of a Al nanocluster on a Al(111) surface can be extracted vertically and repositioned with a Al trimer-apex tip, which allows to rearrange a ten-atom hexagonal nanocluster to a triangular one in a reversible way. The governing mechanism is the atomic tip-surface interaction whose distinct dependence on directions plays a key role in manipulations. [ABSTRACT FROM AUTHOR]

Recent theoretical and experimental results suggested that the silver superlens could be constructed through controlling silver thin film thickness and preparation conditions, and applied in subdiffraction-limited optical imaging and optical lithography. In this work, we report another significant application of silver superlens—ultrahigh density optical data storage. With the silver superlens the subdiffraction-limited pit arrays on an optical disk are dynamically read out and the carrier-to-noise ratio can reach 25 dB for the thin film thickness of 46 nm. The readout laser power and readout velocity have little effect on the carrier-to-noise ratio. Additionally, in our experiment the silver thin film thickness needs to be controlled in the range from 20 to 80 nm. [ABSTRACT FROM AUTHOR]

We study the reliability of the lateral manipulation of a single Cu adatom on a Cu(111) surface with single-atom, dimer and trimer apex tips using both semiempirical and first-principles simulations. The dependence of the manipulation reliability on tip height is investigated. For the single-atom apex tip the manipulation reliability increases monotonically with decreasing tip height. For the dimer and trimer apex tips the manipulation reliability is greatly improved compared to that for the single-atom apex tip over a certain tip-height range. Two kinds of mechanism are found responsible for this improvement. One is the so-called enhanced interaction mechanism in which the lateral tip-adatom interaction in the manipulation direction is improved. The other is the suspended atom mechanism in which the relative lateral trapping ability of the tip is improved due to the strong vertical attraction of the tip on the adatom. Both mechanisms occur in the manipulations with the trimer apex tip, while in those with the dimer apex tip only the former is effective. Moreover, we present a method to realize reversible vertical manipulation of a single atom on a Cu(111) surface with the trimer apex tip, based on its strong vertical and lateral attraction on the adatom. [ABSTRACT FROM AUTHOR]