Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Sakai, Seiji; Mitani, Seiji*; Sugai, Isamu; Takanashi, Koki; Matsumoto, Yoshihiro; Entani, Shiro; Naramoto, Hiroshi*; Avramov, P.; Maeda, Yoshihito
Physical Review B, 83(17), p.174422_1 - 174422_6, 2011/05
Times Cited Count:8 Percentile:34.53(Materials Science, Multidisciplinary)Gu, B.; Sugai, Isamu*; Ziman, T.*; Guo, G. Y.*; Nagaosa, Naoto; Seki, Takeshi*; Takanashi, Koki; Maekawa, Sadamichi
Physical Review Letters, 105(21), p.216401_1 - 216401_4, 2010/11
Times Cited Count:71 Percentile:89.81(Physics, Multidisciplinary)Sugai, Isamu*; Sakai, Seiji; Matsumoto, Yoshihiro; Naramoto, Hiroshi*; Mitani, Seiji*; Takanashi, Koki; Maeda, Yoshihito
Journal of Applied Physics, 108(6), p.063920_1 - 063920_7, 2010/09
Times Cited Count:8 Percentile:33.34(Physics, Applied)Matsumoto, Yoshihiro; Sakai, Seiji; Naramoto, Hiroshi*; Hirao, Norie*; Baba, Yuji; Shimada, Toshihiro*; Sugai, Isamu; Takanashi, Koki; Maeda, Yoshihito
Materials Research Society Symposium Proceedings, Vol.1081 (Internet), 6 Pages, 2008/03
Recently, we have found the appearance of substantial MR ratio (80%) in a C/Co hybrid material. Such the MR ratio cannot be explained enough only by tunnel conduction through Co grains. Therefore, to obtain information about electronic structures of C
/Co hybrid material is necessary. Absorption spectra of C
Co are different from that of pristine C
. In particular, peak intensity corresponding to
(LUMO)
C 1s excitation of C
Co is clearly attenuated. In addition, C 1s photoelectron peak of C
Co slightly shifted to lower binding energy compared to that of pristine C
. These results indicate that 3d electron of Co transfers to
orbital of C
and new electronic states are formed in the C
-Co compound. In fact, XPS spectra of valence excitation region also demonstrate the formation of hybrid orbital near the Fermi level due to the coupling of C
and Co.
Sakai, Seiji; Sugai, Isamu; Mitani, Seiji*; Takanashi, Koki; Matsumoto, Yoshihiro; Naramoto, Hiroshi*; Avramov, P.; Okayasu, Satoru; Maeda, Yoshihito
Applied Physics Letters, 91(24), p.242104_1 - 242104_3, 2007/12
Times Cited Count:30 Percentile:70.87(Physics, Applied)Sakai, Seiji; Yakushiji, Kei*; Mitani, Seiji*; Sugai, Isamu; Takanashi, Koki*; Naramoto, Hiroshi*; Avramov, P.; Lavrentiev, V.*; Narumi, Kazumasa; Maeda, Yoshihito
Materials Transactions, 48(4), p.754 - 758, 2007/04
Times Cited Count:10 Percentile:52.62(Materials Science, Multidisciplinary)Magnetic properties were investigated for the alternately deposited film of C and Co which has found to exhibit tunnel magnetoresistance (MR) of 10-80 %. Magnetic field and temperature dependences of magnetization showed typical superparamagnetic behaviors with the blocking temperature of 40 K. The magnetization curve at 300 K was well fitted by the Langevin function with the size distribution of Co particles, and the mean diameter and size distribution were evaluated to be 3.1 nm and 1 nm, respectively. Based on the magnetic properties, the detailed structure and magnetotransport properties are discussed.
Sakai, Seiji; Sugai, Isamu; Matsumoto, Yoshihiro; Mitani, Seiji*; Takanashi, Koki; Naramoto, Hiroshi*; Avramov, P.; Okayasu, Satoru; Maeda, Yoshihito
no journal, ,
no abstracts in English
Sakai, Seiji; Sugai, Isamu*; Mitani, Seiji*; Takanashi, Koki; Matsumoto, Yoshihiro; Entani, Shiro; Avramov, P.*; Naramoto, Hiroshi*
no journal, ,
Sakai, Seiji; Matsumoto, Yoshihiro; Entani, Shiro; Sugai, Isamu*; Mitani, Seiji*; Takanashi, Koki; Naramoto, Hiroshi*; Maeda, Yoshihito
no journal, ,
no abstracts in English
Sakai, Seiji; Sugai, Isamu*; Mitani, Seiji*; Takanashi, Koki*; Naramoto, Hiroshi*; Avramov, P.; Okayasu, Satoru; Narumi, Kazumasa; Maeda, Yoshihito
no journal, ,
no abstracts in English
Sakai, Seiji; Sugai, Isamu; Mitani, Seiji*; Matsumoto, Yoshihiro; Takanashi, Koki; Naramoto, Hiroshi*; Avramov, P.; Okayasu, Satoru; Maeda, Yoshihito
no journal, ,
Sakai, Seiji; Matsumoto, Yoshihiro; Sugai, Isamu*; Mitani, Seiji*; Takanashi, Koki; Takagi, Yasumasa*; Nakagawa, Takeshi*; Yokoyama, Toshihiko*; Shimada, Toshihiro*; Maeda, Yoshihito
no journal, ,
no abstracts in English
Sakai, Seiji; Matsumoto, Yoshihiro; Sugai, Isamu*; Mitani, Seiji*; Takanashi, Koki; Takagi, Yasumasa*; Nakagawa, Takeshi*; Yokoyama, Toshihiko*; Shimada, Toshihiro*; Naramoto, Hiroshi*; et al.
no journal, ,
no abstracts in English
Sakai, Seiji; Matsumoto, Yoshihiro; Sugai, Isamu*; Mitani, Seiji*; Takanashi, Koki; Naramoto, Hiroshi*; Okayasu, Satoru; Maeda, Yoshihito
no journal, ,
no abstracts in English
Sakai, Seiji; Sugai, Isamu; Yakushiji, Kei*; Mitani, Seiji*; Takanashi, Koki*; Naramoto, Hiroshi; Avramov, P.; Narumi, Kazumasa; Maeda, Yoshihito
no journal, ,
no abstracts in English
Sakai, Seiji; Matsumoto, Yoshihiro; Sugai, Isamu*; Mitani, Seiji*; Takanashi, Koki; Maeda, Yoshihito
no journal, ,
no abstracts in English
Sakai, Seiji; Matsumoto, Yoshihiro; Entani, Shiro; Sugai, Isamu*; Mitani, Seiji*; Takanashi, Koki; Naramoto, Hiroshi*; Maeda, Yoshihito
no journal, ,
no abstracts in English
Sakai, Seiji; Matsumoto, Yoshihiro; Entani, Shiro; Sugai, Isamu*; Mitani, Seiji*; Takanashi, Koki; Naramoto, Hiroshi*; Maeda, Yoshihito
no journal, ,
no abstracts in English
Sakai, Seiji; Matsumoto, Yoshihiro; Entani, Shiro; Sugai, Isamu*; Mitani, Seiji*; Takanashi, Koki; Naramoto, Hiroshi*; Maeda, Yoshihito
no journal, ,
no abstracts in English
Sakai, Seiji; Matsumoto, Yoshihiro; Entani, Shiro; Sugai, Isamu*; Takanashi, Koki; Takagi, Yasumasa*; Nakagawa, Takeshi*; Yokoyama, Toshihiko*; Shimada, Toshihiro*; Naramoto, Hiroshi*; et al.
no journal, ,
We investigated the bias-voltage (V) and temperature (T) dependences of the spin-dependent transport properties of the granular C60-Co films in the current perpendicular to plane (CPP) geometry. At low T, each sample shows much higher MR than the upper limit of TMR (MR=50%) derived from the Julliere's model. From the I-V characteristics, we evaluated the degree of the higher order tunneling process, as a possible cause of the MR enhancement above MR=50%, to be 3-7 (T=2K), which changes depending on the sample composition and device structure. By considering this enhancement effect, we can estimate the spin-polarization at the C60-Co compound/Co interface. The estimated values are remarkably high, i.e., P=75% at zero temperature, compared to Co crystal(P=30%), and almost independent of the samples. The detailed results on the transport properties and X-ray magnetic circular dichroism spectroscopy were presented in the conference.