Published papers

We investigate the Co thickness dependence of the structural and magnetic properties of Co thin-film electrodes sandwiched between borate glasses in spin quantum cross (SQC) devices that utilize stray magnetic fields. We also calculate the Co thickness dependence of the stray field between the two edges of Co thin-film electrodes in SQC devices using micromagnetic simulation. The surface roughness of Co thin films with a thickness of less than 20 nm on borate glasses is shown to be as small as 0.18 nm, at the same scanning scale as the Co film thickness, and the squareness of the hysteresis loop is shown to be as large as 0.96-1.0. As a result of the establishment of polishing techniques for Co thin-film electrodes sandwiched between borate glasses, we successfully demonstrate the formation of smooth Co edges and the generation of stray magnetic fields from Co edges. Theoretical calculation reveals that a strong stray field beyond 6 kOe is generated when the Co thickness is greater than 10 nm at a junction gap distance of 5 nm. From these experimental and calculation results, it can be concluded that SQC devices with a Co thickness of 10-20 nm can be expected to function as spin-filter devices. (C) 2015 AIP Publishing LLC.

Analysis of achieving a clean environment in a connected box-units system is performed. By feedback of outlet air into the inlet of the box-unit, the steady-state airborne-particle-count in the system becomes independent of the ambient particle count and depends little on the particle-arrest efficiency of the filter. It is demonstrated that ISO 3 (209D Class 1) cleanliness in an inexpensive compact manner with the versatile extensive connected box-units system can be realised, no matter how dusty the ambient.

We have derived a formula for current density-voltage (J-V) characteristics in nanoscale tunnel junctions, consisting of thin insulating barriers sandwiched between two thin metal films whose edges are crossing. As a result of the calculation of J-V characteristics, the current density decreases with decreasing the metal thickness below 30-40nm due to the quantization of the out-of-plane direction in the metal films. Moreover, as a result of the fabrication of Ni/NiO/Ni nanoscale tunnel junctions with a junction area of 24 x 24 nm(2), we have found that experimental J-V characteristics show a good fit to calculation results with a barrier height of 0.8 eV and a barrier thickness of 0.63 nm. These results indicate that the derived formula is useful for the evaluation of the barrier height and the barrier thickness and our fabrication method can be expected as a new technique for the creation of nanoscale tunnel junctions. (C) 2010 The Japan Society of Applied Physics

Sodium ions in 25NaO(1/2)-6LaO(3/2)-6GeO(2)-63PO(5/2) (mol%) glasses were substituted with protons using corona discharge treatment (CDT) under a H-2 atmosphere. The substitution of sodium ion to proton proceeded from the anode side to the cathode side with con degrees stant current flow during the CDT. A crystalline free and transparent glass plate of 0.3 mm thickness was obtained after CDT for 96 h. The maximum decrease rate from sodium ion to proton was 78 +/- 10%. The proton conductivity of 8.5 x 10(-4) S/cm was attained at 400C. (C) 2017 Elsevier B.V. All rights reserved.