Crystal-to-crystal transformation from tri- to mononuclear Cu(II) complex with a sugar-derived ligand via proton transfer reaction and rearrangement of hydrogen bonding networks

Treatment of a glycosylamine derived Cu(II) complex with ethylamine resulted in crystal-to-crystal transformation from trinuclear complex [Cu3(L1)2(EtNH2)2(MeOH)2]x2MeOHxCHCl3 (2x2MeOHxCHCl3) to a dimeric structure of mononuclear complex [Cu(HL1)(EtNH2)] (3) through proton transfer reaction and rearrangement of hydrogen bonding networks.     

New CO tolerant electro-catalysts exceeding Pt-Ru for the anode of fuel cells

Novel types of CO tolerant electro-catalysts from Pt and organic metal complexes that are far superior to Pt-Ru and practically usable as anode catalysts in reformate gas fuel cells with 100 ppm CO tolerance have been developed.     

Transient domain wall displacement under spin-polarized current pulses

This paper investigates the non steady-state displacement of magnetic domain walls in a nanostrip submitted to a time-dependent spin-polarized current flowing along the nanostrip. First, numerical micromagnetic simulations show that a domain wall can move under application of a current pulse, and that the displacement resulting from a conversion of the domain wall structure is quantized. The numerical findings are subsequently explained in the framework of simplified analytic models, namely the 1D model and the point-core vortex model. We then introduce the concept of an angle linked to the magnetization of a general domain wall, and show that it allows understanding the transient phenomena quite generally. Simple analytic formulas are derived and compared to experiments. For this, charts are given for the key parameters of the domain wall mechanics, as obtained from numerical micromagnetic simulations. We finally discuss the limitations of this work, by looking at the influence of temperature elevation under current, presence of a non-adiabatic term, and of disorder.     

Photo-modification and synthesis of semiconductor nanocrystals

Both photo-oxidation and photosynthesis manifest a strong interaction between nanoparticles and photons due to the large surface area-to-volume ratio. The final sizes of the semiconductor nanocrystals are determined by the photon energy during these phenomena. The photosynthesis is demonstrated in a Si-rich oxide and is similar to thermal synthesis, which involves the decomposition of SiO_x into Si and SiO₂, that is well known and often employed to form Si or Ge nanocrystals embedded in SiO₂ by annealing SiO_x at high temperature. However, photosynthesis is much faster, and allows the low-temperature growth of Si nanocrystals and is found to be pronounced in the SiO nanopowder, which is made by thermal CVD using SiH₄ and O₂. The minimum laser power required for the photosynthesis in the SiO nanopowder is much lower than in the Si-rich oxide formed by the co-sputtering of Si and SiO₂. This is attributed to the weak bond strength of Si-Si and Si-O in the SiO nanopowder. Photosynthesis, which can control the size and position of Si nanocrystals, is a novel nanofabrication technique making the best use of the strong interaction between photons and nanoparticles.     

Local magnetic fields in the Mo layer of Mo/Fe multilayer

Using time-differential perturbed-angular-correlation technique, hyperfine fields at ⁹⁹Tc (←⁹⁹Mo) in the Mo layers in polyimide/Fe (10 nm)/[Mo (t _Mo)/Fe (2.0 nm)]₁₂₀, where t _Mo is in the range between 0.4 and 1.5 nm, were measured at room temperature. The values of the magnetic hyperfine field at the Mo/Fe interface were extracted. Its dependence on the Mo layer thickness suggests that the oscillatory interlayer exchange coupling is due to conduction electron spin polarization in the Mo layer, which in turn is produced via an RKKY-type mechanism.     

Effective temperatures of a driven system near jamming

Fluctuations in a model of a sheared, zero-temperature foam are studied numerically. Five different quantities that independently reduce to the true temperature in an equilibrium thermal system are calculated. One of the quantities is calculated up to an unknown coefficient. The other four quantities have the same value and all five have the same shear-rate dependence. These results imply that statistical mechanics is useful for the system even though it is far from thermal equilibrium.     

Enhancement of CsLiB(6)O(10) surface-damage resistance by improved crystallinity and ion-beam etching

The surface laser-induced damage threshold (LIDT) of CsLiB(6)O(10) (CLBO) crystal was enhanced twofold with improved crystallinity and ion-beam etching. For crystals with high crystal quality (bulk LIDT, 15.0-19.0 GW/cm(2)), the surface LIDT was 1.4-fold higher than for those with conventional crystal quality (bulk LIDT, 9.0-12.0 GW/cm(2)). In addition, removal of residual surface-polishing compounds by means of ion-beam etching can further enhance the surface LIDT by another 1.5-fold. Thus, CLBO crystals with high crystal quality and ion-beam etching are now more reliable for high-power UV light generation.     

A SAXS study of the gelation process of silicon and titanium alkoxides

The gelation process of silicon ethoxide and titanium iso-propoxide solutions was studied as a function of water content and reaction time by small-angle X-ray scattering (SAXS). Approaching the gelation points, the SAXS intensities for titanium tetra-iso-propoxide solutions start to follow a power-law decay in the Porod region, except for a H₂O/Ti ratio greater than 4. For silicon ethoxide solutions, the fractal dimension, d_f, measured for aggregated clusters increases continually with the H₂O/Si ratio and can be related to the spinnability of the solutions. For solutions of both silicon and titanium alkoxides, a solution of fractal dimension d_f < 1.79 shows spinnability, whereas solutions having d_f > 1.79 and no fractal structures do not show spinnability.     

Ruthenium Tris‐bipyridine Single‐Molecule Junctions with Multiple Joint Configurations

Single‐molecule junctions are of particular interest in molecular electronics. To realize molecular electronic devices, it is crucial that functional single‐molecule junctions are connected to each other by using joint units on the atomic scale. However, good joint units have not been reported because controlling the charge transport directions through the junctions is not trivial. Here, we report a joint unit that controls and changes the charge transport directions through the junctions, by using a ruthenium–tris‐bipyridine (RuBpy) complex. The RuBpy single‐molecule junction was fabricated with scanning tunnelling microscopy‐based break junction techniques. The RuBpy single‐molecule junction showed two distinct high and low conductance states. The two states were characterized by the conductance measurement, the correlation analysis, and the comparative experiment of bipyridine (Bpy), which is the ligand unit of RuBpy. We demonstrate that the Ru complex has multiple charge transport paths, where the charge is carried vertically and horizontally through the complex depending on the path.