Search

Your search keyword '"Yasuhiro Shirahata"' showing total 4 results
Start Over Author "Yasuhiro Shirahata" Publisher aip publishing llc
4 results on '"Yasuhiro Shirahata"'

1. Electric-field-driven domain wall dynamics in perpendicularly magnetized multilayers

Author

Diego López González, Yasuhiro Shirahata, Ben Van de Wiele, Kévin J. A. Franke, Arianna Casiraghi, Tomoyasu Taniyama, and Sebastiaan van Dijken

Subjects
Physics, QC1-999
Abstract

We report on reversible electric-field-driven magnetic domain wall motion in a Cu/Ni multilayer on a ferroelectric BaTiO3 substrate. In our heterostructure, strain-coupling to ferroelastic domains with in-plane and perpendicular polarization in the BaTiO3 substrate causes the formation of domains with perpendicular and in-plane magnetic anisotropy, respectively, in the Cu/Ni multilayer. Walls that separate magnetic domains are elastically pinned onto ferroelectric domain walls. Using magneto-optical Kerr effect microscopy, we demonstrate that out-of-plane electric field pulses across the BaTiO3 substrate move the magnetic and ferroelectric domain walls in unison. Our experiments indicate an exponential increase of domain wall velocity with electric field strength and opposite domain wall motion for positive and negative field pulses. The application of a magnetic field does not affect the velocity of magnetic domain walls, but independently tailors their internal spin structure, causing a change in domain wall dynamics at high velocities.

Published
2017
Full Text
View/download PDF

2. Microstructure analysis of spherical silicon solar cells with SnOx:Fy layers

Author

Youichi Kanamori, Takeo Oku, Mikio Murozono, and Yasuhiro Shirahata

Subjects
Materials science, Silicon, business.industry, Annealing (metallurgy), chemistry.chemical_element, Microstructure, Chemical reaction, Optics, Lattice constant, chemistry, Chemical engineering, Fluorine, business, Tin, Spectroscopy
Abstract

Microstructures of spherical silicon solar cells with SnOx:Fy layers were investigated. Lattice constants of annealed SnOx:Fy layers were larger than those of as-prepared SnOx:Fy layers due to reduction of defects. From energy dispersive X-ray spectroscopy, it was confirmed that oxygen, fluorine and tin were diffused over silicon spheres, and composition ratios of the SnOx:Fy layers were changed by annealing. The mechanism of chemical reaction of SnO2 and SnO2/metal interface were also discussed.

Published
2016
Full Text
View/download PDF

3. Evaluation of photovoltaic power generation system using spherical silicon solar cells and SiC-FET inverter

Author

Akio Shimono, Taisuke Matsumoto, Takeo Oku, Masashi Yasuda, Mikio Murozono, Yasuhiro Shirahata, Yoshikazu Takeda, and Koichi Hiramatsu

Subjects
Materials science, Silicon, business.industry, Photovoltaic system, Electrical engineering, chemistry.chemical_element, Maximum power point tracking, Power (physics), chemistry.chemical_compound, chemistry, Silicon carbide, Optoelectronics, Inverter, Grid-tie inverter, Field-effect transistor, business
Abstract

A photovoltaic power generation system using spherical silicon (Si) solar cells and silicon carbide (SiC) field effect transistor (FET) inverter for photovoltaic applications was constructed and evaluated. The spherical Si solar cells were connected to the SiC-FET inverter and were used as a power source. Comparing the photovoltaic power generation system using an ordinary Si-FET inverter, direct current-alternating current conversion efficiencies of the SiC-FET inverter were improved due to reduction of power loss in the SiC-FET inverter.

Published
2016
Full Text
View/download PDF

4. Fabrication and photovoltaic properties of ZnO nanorods/perovskite solar cells

Author

Takeo Oku, Tsuyoshi Akiyama, Kohei Tanaike, Kazuya Fujimoto, Jeyadevan Balachandran, Yasuhiro Shirahata, and Atsushi Suzuki

Subjects
Fabrication, Nanostructure, Materials science, business.industry, Energy conversion efficiency, Optoelectronics, Nanorod, Nanotechnology, Photovoltaic effect, business, Layer (electronics), Perovskite (structure), Chemical bath deposition
Abstract

ZnO nanorods/perovskite solar cells with different lengths of ZnO nanorods were fabricated. The ZnO nanorods were prepared by chemical bath deposition and directly confirmed to be hexagon-shaped nanorods. The lengths of the ZnO nanorads were controlled by deposition condition of ZnO seed layer. Photovoltaic properties of the ZnO nanorods/CH3NH3PbI3 solar cells were investigated by measuring current density-voltage characteristics and incident photon to current conversion efficiency. The highest conversion efficiency was obtained in ZnO nanorods/CH3NH3PbI3 with the longest ZnO nanorods.

Published
2016
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results