Akinobu Yamaguchi

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We report direct observation of current-driven magnetic domain wall (DW) displacement by using a well-defined single DW in a microfabricated magnetic wire with submicron width. Magnetic force microscopy visualizes that a single DW introduced in a wire is displaced back and forth by positive and negative pulsed current, respectively. The direct observation(More)
We present the first results for neutral-kaon mixing using (2+1)-flavors of domain-wall fermions. A new approach is used to extrapolate to the physical up and down quark masses from our numerical studies with pion masses in the range 240-420 MeV; only SU(2)_{L}xSU(2)_{R} chiral symmetry is assumed and the kaon is not assumed to be light. Our main result is(More)
We report an omnidirectional electrical spectroscopy setup for studying the spin dynamics in a nanoscale magnet. It has a measureable solid angle range comprising about 50% of the total range and allows the magnetoresistance and spin-torque diode signal to be measured simultaneously at any angle to the magnetization. This setup can provide detailed(More)
Rapid and sensitive chemical sensing using microfluidic device equipped with sterically-bulky three-dimensional gold nanostructure (Au3D) was demonstrated. Au3D was expected as surface enhanced Raman scattering (SERS) active structure. Au3D was fabricated by convective selfassembly known as “coffee-ring” of the mixed solution of gold colloidal(More)
We present results for some of the light baryon masses and their excited states in 2+1 flavour domain wall QCD. We considered several lattice spacings, with the DBW2 and Iwasaki gauge actions and different sea quark masses on a volume of 163 × 32 and a fifth dimension of size 8. All data were generated on the QCDOC machines. Despite large residual massses(More)
Counterfeits are now world-wide issue. An anti-counterfeit technology with high security level (unclonable), high through-put rate of authentication, and low cost is desirable. Nanotag of plasmonic nanostructure with surface enhanced Raman scattering (SERS) activity is promised for the ideal authentication. The gold nanoparticle (AuNP) self-assemblies were(More)
X-ray radiolysis of a Cu(CH3COO)2 solution was observed to produce caltrop-shaped particles of cupric oxide (CuO, Cu2O), which were characterized using high-resolution scanning electron microscopy and micro-Raman spectrometry. X-ray irradiation from a synchrotron source drove the room-temperature synthesis of submicrometer- and micrometer-scale cupric oxide(More)
The deposition of caltrop-shaped cupric oxide particles synthesized by X-ray radiolysis process was performed on a silicon substrate. The use of alcohol such as methanol and ethanol as an additive enabled the nucleation and growth of caltrop-shaped cupric particles, while no particles were produced in a cupric acetate solution without any alcohol with X-ray(More)
The microfabrication technique based on X-ray lithography has recently been applied to construct PTFE-based microstructures. This paper attempts to fabricate an integrated waveguide Butler matrix for short millimeter-wave using X-ray lithography. First, a cruciform 3-dB directional coupler and an intersection circuit are designed at 180 GHz. Then, a(More)
We systematically measured the spin torque diode spectra of a magnetic tunnel junction nanoelement as a function of external magnetic field and field angle using a homemade quasi-omnidirectional broadband electrical spectrometer. The electrical spectroscopies reveal a significant higher-order spin wave modes excited in the free layer, which is substantiated(More)