Takashi Yamamoto 교수

ZnO films with an excellent crystal orientation and surface flatness have been prepared by high-deposition-rate rf planar-magnetron sputtering. A detailed study of these films has been carried out using x-ray diffraction, scanning electron microscopy, reflection electron diffraction, optical measurement, and electromechanical measurement. These films have the c-axis perpendicular to the substrate. The value of the standard deviation angle σ of the c-axis orientation distribution is smaller than

Spins of negatively charged nitrogen-vacancy (NV${}^{\ensuremath{-}}$) defects in diamond are among the most promising candidates for solid-state qubits. The fabrication of quantum devices containing these spin-carrying defects requires position-controlled introduction of NV${}^{\ensuremath{-}}$ defects having excellent properties such as spectral stability, a long spin coherence time, and a stable negative charge state. Nitrogen ion implantation and annealing enable the positioning of NV${}^{\e

Lanthanum‐modified lead titanate ceramics with a tetragonality of c/a = 1.028 to 1.000 were hot‐pressed and the dielectric, electromechanical, optical, and mechanical properties were investigated. With decreasing c/a , the Curie point, remnant polarization, coercive field, and electromechanical coupling factors decrease and the transmittance increases. The internal stress was measured using a microindentation technique by changing the indent load. The internal stress increases with increasing c/

A novel photocontrollable magnetic thin film consisting of amphiphilic azobenzene cations, a smectite clay, and Prussian Blue has been designed and prepared by using the Langmuir−Blodgett method and an ion-exchange reaction. This magnetic thin film possesses a well-organized nanoscale layered structure. Reversible photoisomerization of the azobenzene chromophore realized photoswitching of the magnetization. The changes in the magnetization values were estimated to be ca. 11%. This figure was muc

Thin films of cobalt-iron cyanide (Co-Fe Prussian blue) have been fabricated by means of the modified Langmuir-Blodgett (LB) method using a smectite clay mineral (montmorillonite). In this combined method, clay LB films play a template role in the formation of the Co-Fe Prussian blue thin layer. The films were revealed to possess a well-organized structure not only in perpendicular directions to the film surface but also in parallel directions to the film surface. The photoinduced electron trans

Ionized nitrogen molecules (${}^{15}$N${}_{2}^{+}$) are used as efficient point sources for creating NV${}^{\ensuremath{-}}$ pairs in diamond with nanoscale spatial separation and up to 55 kHz magnetic coupling strength. Co-implantation of ${}^{12}$C${}^{+}$ increased the yield of pairs, and a ${}^{13}$C-depleted diamond allowed 0.65 ms coherence times to be obtained. Further coupling to a third dark spin provided a strongly coupled three-spin register. These results mark an important step towar

Abstract A simple fabrication, scalable to centimeter scale, of a permeable membrane made of block copolymer containing molecular transport channels is demonstrated by coating photo‐crosslinkable liquid‐crystalline block copolymer, consisting of poly(ethylene oxide) (PEO) and poly(methacrylate) (PMA) bearing stilbene (Stb) mesogens in the side chains (PEO 114 ‐ b ‐PMA(Stb) 52 ), onto a sacrificial cellulose acetate film substrate. After thermal annealing, perpendicularly aligned and hexagonally

A stereoselective and electrocatalytic coupling reaction of isoeugenol has been reported for the first time in a 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP)/boron-doped diamond (BDD) electrode system. This particular C-C bond formation and diastereoselectivity is driven by a solvate interaction between the radical species and another isoeugenol molecule. Due to an electrocatalytic cycle, only understoichiometric amounts of charge are necessary. Since electric current is directly employed as the oxi

Ultrathin films composed of titania nanosheets and Prussian Blue were prepared by using the modified Langmuir-Blodgett technique. The ultrathin films could be deposited in a layer-by-layer manner with lamellar structure. Upon band gap excitation of titania nanosheets, the generated electrons were injected into ferromagnetic Prussian Blue, resulting in reduction to paramagnetic Prussian White. It was revealed that the reaction could proceed only in the presence of hole-scavenging interlayer water

Abstract Lanthanum modified lead titanate, (Pb0·775La0·15)TiO3 ceramics with a tetragonality of c/a = 1·024 were hot-pressed and the anisotropy of internal stress generated by applying a poling field were measured using a microindentation technique. In this specimen with a grain size of Gs=3·0 μm, the internal stresses in the directions perpendicular and parallel to the DC poling field were 151 and 35 MN/m2, respectively. The results are explained by the crack-extentional and compressive forces,