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Uchida, Kenichi*; Ota, Takeru*; Adachi, Hiroto; Xiao, J.*; Nonaka, Tatsumi*; Kajiwara, Yosuke*; Bauer, G. E. W.*; Maekawa, Sadamichi; Saito, Eiji
Journal of Applied Physics, 111(10), p.103903_1 - 103903_11, 2012/05
Times Cited Count：124 Percentile：96.11(Physics, Applied)Uchida, Kenichi*; Adachi, Hiroto; An, Toshu*; Ota, Takeru*; Toda, Masaya*; Hillebrands, B.*; Maekawa, Sadamichi; Saito, Eiji
Nature Materials, 10(10), p.737 - 741, 2011/10
Times Cited Count：232 Percentile：98.47(Chemistry, Physical)We show that, using a NiFe/Pt bilayer wire on an insulating sapphire plate, electrons in the wire recognize their position on the sapphire. Under a temperature gradient in the sapphire, surprisingly, the voltage generated in the Pt layer is shown to reflect the wire position, although the wire is isolated both electrically and magnetically. This non-local voltage due to the coupling of spins and phonons: the only possible carrier of information in this system. We demonstrate this coupling by directly injecting sound waves, which realizes the acoustic spin pumping. Our finding provides a persuasive answer to the long-range nature of the spin Seebeck effect, and it opens the door to "acoustic spintronics" in which sound waves are exploited for constructing spin-based devices.
Uchida, Kenichi*; Xiao, J.*; Adachi, Hiroto; Oe, Junichiro; Takahashi, Saburo; Ieda, Junichi; Ota, Takeru*; Kajiwara, Yosuke*; Umezawa, Hiromitsu*; Kawai, Hirotaka*; et al.
Nature Materials, 9(11), p.894 - 897, 2010/11
Times Cited Count：1050 Percentile：99.88(Chemistry, Physical)Thermoelectric generation is an essential function in future energy-saving technologies. However, it has so far been an exclusive feature of electric conductors, a situation which limits its application; conduction electrons are often problematic in the thermal design of devices. Here we report electric voltage generation from heat flowing in an insulator. We reveal that, despite the absence of conduction electrons, the magnetic insulator LaY
Fe
O
can convert a heat flow into a spin voltage. Attached Pt films can then transform this spin voltage into an electric voltage as a result of the inverse spin Hall effect. The experimental result require us to introduce a thermally activated interface spin exchange between LaYFeO and Pt. Our findings extend the range of potential materials for thermoelectric applications and provide a crucial piece of information for understanding the physics of the spin Seebeck effect.
Uchida, Kenichi*; Adachi, Hiroto; Ota, Takeru*; Nakayama, Hiroyasu*; Maekawa, Sadamichi; Saito, Eiji
Applied Physics Letters, 97(17), p.172505_1 - 172505_3, 2010/10
Times Cited Count：621 Percentile：99.68(Physics, Applied)Osawa, Hideaki; Ota, Kunio; Hama, Katsuhiro; Sawada, Atsushi; Takeuchi, Shinji; Amano, Kenji; Saegusa, Hiromitsu; Matsuoka, Toshiyuki; Miyamoto, Tetsuo; Toyoda, Gakuji; et al.
JAEA-Research 2008-085, 742 Pages, 2008/11
JAEA-Research-2008-085-1.pdf:26.22MBJAEA-Research-2008-085-2.pdf:16.64MBJAEA-Research-2008-085-3.pdf:28.27MB
This report shows the results the project for the establishment of comprehensive site characterization technology, entrusted from Natural Resources and Energy Agency, Ministry of Economy, Trade and Industry Natural Resources and Energy Agency in 2007.
Re populated by the 
reaction from laser Compton scattering 
rays at the electron storage ring NewSUBARUHayakawa, Takehito; Miyamoto, Shuji*; Hayashi, Yukio; Kawase, Keigo*; Horikawa, Ken*; Chiba, Satoshi; Nakanishi, Kosuke*; Hashimoto, Hisanobu*; Ota, Takeshi*; Kando, Masaki; et al.
Physical Review C, 74(6), p.065802_1 - 065802_5, 2006/12
Times Cited Count：29 Percentile：82.75(Physics, Nuclear)We report a half-life of the ground state of Re populated by the 
ReRe reaction with the laser Compton scattering -rays generated through relativistic engineering. The -rays are provided at the electron storage ring NewSUBARU. The previous experiment using deuteron-induced reactions has yielded a recommended half-life of the 3
ground state of Re to be 38.0 
0.5 d, including a possible contribution from the 8
isomer (
= 169 8 d) of Re since the presence of the isomer was not known at that time. In contrast, the reaction has an advantage to selectively populate the ground state because this reaction does not bring large angular momentum. The measured half-life of 35.4 0.7 d is shorter than the previous half-life by about 7%. This difference is crucial for applications using the activation method.
W, 
Re and 
Os; Implications for the Re-Os cosmochronologyShizuma, Toshiyuki; Utsunomiya, Hiroaki*; Mohr, P.*; Hayakawa, Takehito; Goko, Shinji*; Makinaga, Ayano*; Akimune, Hidetoshi*; Yamagata, Tamio*; Ota, Masahisa*; Ogaki, Hideaki*; et al.
Physical Review C, 72(2), p.025808_1 - 025808_9, 2005/08
Times Cited Count：44 Percentile：90.03(Physics, Nuclear)Cross sections of the W, Re, Os(
) reactions were measured using quasi-monochromatic photon beams from laser Compton scattering (LCS) with average energies from 7.3 to 10.9 MeV. The results are compared with the predictions of Hauser-Feshbach statistical calculations using four different sets of input parameters. In addition, the inverse neutron capture cross sections were evaluated by constraining the model parameters, especially the 
strength function, on the basis of the experimental data. The present experiment helps to further constrain the correction factor 
for the neutron capture on the 9.75 keV state in Os. Implications of to the Re-Os cosmochronology are discussed with a focus on the uncertainty in the estimate of the age of the Galaxy.
-rays at NewSUBARUHayakawa, Takehito; Miyamoto, Shuji*; Hayashi, Yukio; Kawase, Keigo*; Horikawa, Ken*; Chiba, Satoshi; Nakanishi, Kosuke*; Hashimoto, Hisanobu*; Ota, Takeshi*; Kando, Masaki; et al.
no journal, ,
no abstracts in English
Re populated by photodisintegration reaction with Laser Compton scattering -rays at NewSUBARUHayakawa, Takehito; Miyamoto, Shuji*; Hayashi, Yukio; Kawase, Keigo*; Horikawa, Ken*; Chiba, Satoshi; Nakanishi, Kosuke*; Hashimoto, Hisanobu*; Ota, Takeshi*; Kando, Masaki; et al.
no journal, ,
no abstracts in English
Hama, Katsuhiro; Amano, Kenji; Saegusa, Hiromitsu; Miyamoto, Tetsuo; Toyoda, Gakuji; Ota, Kunio
no journal, ,
none
Segawa, Mariko; Nagai, Yasuki*; Masaki, Tomohiro*; Temma, Yasuyuki*; Shima, Tatsushi*; Makii, Hiroyuki*; Mishima, Kenji*; Ueda, Hitoshi*; Nakayoshi, Akira*; Ota, Takeshi*; et al.
no journal, ,
Re-Os pair is known as the most promising nuclear cosmochronometer with considerable potential. However, there remains non-trivial problems related to an excited neutron capture reaction of Os at a stellar temperature. Firstly, Os is produced and depleted by the slow process nucleosynthesis. Hence, it is necessary to obtain both the production and depletion rates of Os. Secondly, Os is depleted not only by its ground state neutron capture reaction but also by an excited state neutron capture reaction of Os in a stellar temperature. In the present study, we have measured the neutron capture reaction cross sections for Os, Os and 
Os accurately and neutron inelastic scattering reaction cross section for Os off the ground state of Os to its 9.75-keV first excited statein the neutron energy range from 10 to 100 keV. The measurements of the neutron capture reactions have been carried out by detecting a prompt -ray by means fan anti-Compton NaI(Tl) spectrometer. The (n, n') reaction cross section for Os has been measured with use of four 
Li-glass scintillation detectors. Based on these new capture cross sections, we reestimate on the basis of a careful reaction cross section calculation the correction factor F for the neutron capture on the 9.75-keV first excited state in Os as a function of stellar temperature, as required to derive the age of the galaxy within the Re-Os chronology.
-rays at NewSUBARUHayakawa, Takehito; Shizuma, Toshiyuki; Miyamoto, Shuji*; Amano, Sho*; Horikawa, Ken*; Hayashi, Yukio; Kawase, Keigo; Kando, Masaki; Kikuzawa, Nobuhiro; Chiba, Satoshi; et al.
no journal, ,
no abstracts in English
