Effects of growth temperature and growth rate on polytypes in gold-catalyzed GaAs nanowires studied by in situ X-ray diffraction

Takahashi, Masamitsu; Kozu, Miwa*; Sasaki, Takuo

Japanese Journal of Applied Physics, 55(4S), p.04EJ04_1 - 04EJ04_4, 2016/04

https://doi.org/10.7567/JJAP.55.04EJ04

Anomalous lattice deformation in GaN/SiC(0001) measured by high-speed synchrotron X-ray diffraction

Sasaki, Takuo; Ishikawa, Fumitaro*; Takahashi, Masamitsu

Applied Physics Letters, 108(1), p.012102_1 - 012102_5, 2016/01

AA2015-0769.pdf:2.43MB

https://doi.org/10.1063/1.4939450

Mechanisms determining the structure of gold-catalyzed GaAs nanowires studied by in situ X-ray diffraction

Takahashi, Masamitsu; Kozu, Miwa*; Sasaki, Takuo; Hu, W.*

Crystal Growth & Design, 15(10), p.4979 - 4985, 2015/10

https://doi.org/10.1021/acs.cgd.5b00915

Study of semiconductor growth mechanism using in situ synchrotron X-ray diffraction

Takahashi, Masamitsu

Nihon Kessho Seicho Gakkai-Shi, 42(3), p.201 - 209, 2015/10

AA2015-0739.pdf:0.82MB

http://id.ndl.go.jp/bib/026842879

Spontaneous formation of suboxidic coordination around Co in ferromagnetic rutile TiCoO film

Hu, W.*; Hayashi, Koichi*; Fukumura, Tomoteru*; Akagi, Kazuto*; Tsukada, Masaru*; Happo, Naohisa*; Hosokawa, Shinya*; Owada, Kenji; Takahashi, Masamitsu; Suzuki, Motohiro*; et al.

Applied Physics Letters, 106(22), p.222403_1 - 222403_5, 2015/06

https://doi.org/10.1063/1.4921847

Present state of TEM-SXES analysis and its application to SEM aiming chemical analysis of bulk materials

Terauchi, Masami*; Takahashi, Hideyuki*; Handa, Nobuo*; Murano, Takanori*; Koike, Masato; Imazono, Takashi; Koeda, Masaru*; Nagano, Tetsuya*; Sasai, Hiroyuki*; Oue, Yuki*; et al.

Microscopy and Microanalysis, 20(Suppl.3), p.682 - 683, 2014/08

https://doi.org/10.1017/S1431927614005133

X-rays originate form electronic transitions from valence bands (VB, bonding electron states) to inner-shell electron levels inform us energy states of bonding electrons. We have developed the SXES spectrometers attaching to TEM, EPMA, and SEM. A spectrometer has an energy range of 50-4000 eV by using four varied-line-spacing gratings. Applications of TEM-SXES instrument to C have revealed characteristic energy distribution of bonding electrons. Carbon K-emission spectra of C crystals showed that both the peak structures in - and -bands and the characteristic dip structure between the - and -bonding states in monomer-C disappear in the most polymerized-C crystals. Bulk specimens were examined by applying SXES to a SEM. Al L-emission spectra of intermetallic compounds of AlAu, AlCo, and aluminum showed different intensity distributions due to different band structures originating from different crystal structures.

Application of capillary electrophoresis with laser-induced fluorescence detection for the determination of trace neodymium in spent nuclear fuel using complexation with an emissive macrocyclic polyaminocarboxylate probe

Haraga, Tomoko; Saito, Shingo*; Sato, Yoshiyuki; Asai, Shiho; Hanzawa, Yukiko; Hoshino, Hitoshi*; Shibukawa, Masami*; Ishimori, Kenichiro; Takahashi, Kuniaki

Analytical Sciences, 30(7), p.773 - 776, 2014/07

https://doi.org/10.2116/analsci.30.773

A simple and rapid method with low radiation exposure risk was developed for the determination of neodymium in spent nuclear fuel by CE with LIF detection using a fluorescent ligand having a macrocyclic hexadentate polyaminocarboxylate structure. The concentration of Nd(III) in a spent nuclear fuel sample was determined with no interference from various matrix elements, including lanthanides and uranium (at a 200-fold excess), with 92 3% recovery. This is due to method's high resolution based on establishing a ternary complex equilibrium during migration in which the hydroxyl ion plays an auxiliary role.

Anomalous temperature dependence of current-induced torques in CoFeB/MgO heterostructures with Ta-based underlayers

Kim, J.*; Sinha, J.*; Mitani, Seiji*; Hayashi, Masamitsu*; Takahashi, Saburo*; Maekawa, Sadamichi; Yamanouchi, Michihiko*; Ohno, Hideo*

Physical Review B, 89(17), p.174424_1 - 174424_8, 2014/05

https://doi.org/10.1103/PhysRevB.89.174424

We have studied the underlayer thickness and temperature dependencies of the current-induced effective field in CoFeB/MgO heterostructures with Ta-based underlayers. The underlayer thickness at which the effective field saturates is found to be different between the two orthogonal components of the effective field; i.e., the dampinglike term tends to saturate at a smaller underlayer thickness than the fieldlike term. For large underlayer thickness films in which the effective field saturates, we find that the measurement temperature significantly influences the size of the effective field. A striking difference is found in the temperature dependence of the two components: the dampinglike term decreases whereas the fieldlike term increases with increasing temperature. Using a simple spin diffusion-spin transfer model, we find that all of these results can be accounted for provided the real and imaginary parts of an effective spin mixing conductance are negative. These results imply that either spin transport in this system is different from conventional metallic interfaces or effects other than spin diffusion into the magnetic layer need to be taken into account in order to model the system accurately.

Monitoring of airborne C discharge at RI facilities; A Comparison of collection and oxidation methods

Ueno, Yumi; Koarashi, Jun; Iwai, Yasunori; Sato, Junya; Takahashi, Teruhiko; Sawahata, Katsunori; Sekita, Tsutomu; Kobayashi, Makoto; Tsunoda, Masahiko; Kikuchi, Masamitsu

Hoken Butsuri, 49(1), p.39 - 44, 2014/03

http://doi.org/10.5453/jhps.49.39

http://doi.org/10.5453/jhps.49.2

The Japan Atomic Energy Agency has conducted a monthly monitoring of airborne C discharge at the forth research building (RI facility) of the Tokai Research and Development Center. In the current monitoring, C, which exists in various chemical forms in airborne effluent, is converted into CO with CuO catalyst and then collected using monoethanolamine (MEA) as CO absorbent. However, this collection method has some issues on safety management because the CuO catalyst requires a high heating temperature (600C) to ensure a high oxidation efficiency and the MEA is specified as a poisonous and deleterious substance. To establish a safer, manageable and reliable method for monitoring airborne C discharge, we examined collection methods that use different CO absorbents (MEA and Carbo-Sorb E) and oxidation catalysts (CuO, Pt/Alumina and Pd/ZrO). The results showed 100% CO collection efficiency of MEA during a 30-day sampling period under the condition tested. In contrast, Carbo-Sorb E was found to be unsuitable for the monthly-long CO collection because of its high volatile nature. Among the oxidation catalysts, the Pd/ZrO showed the highest oxidation efficiency for CH at a lower temperature.

Real-time observation of crystallographic tilting InGaAs layers on GaAs offcut substrates

Nishi, Toshiaki*; Sasaki, Takuo; Ikeda, Kazuma*; Suzuki, Hidetoshi*; Takahashi, Masamitsu; Shimomura, Kenichi*; Kojima, Nobuaki*; Oshita, Yoshio*; Yamaguchi, Masafumi*

AIP Conference Proceedings 1556, p.14 - 17, 2013/09

https://doi.org/10.1063/1.4822188