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Journal Articles

Structure analysis of asymmetric interface using spin-contrast-variation neutron reflectometry

Kumada, Takayuki; Miura, Daisuke*; Akutsu, Kazuhiro*; Oku, Takayuki; Torikai, Naoya*; Niizeki, Tomotake*

Hamon, 32(4), p.165 - 168, 2022/11

We demonstrated the advantage of spin-contrast-variation neutron reflectometry on the structure analysis of buried interface between resin and porous silica layers. The interface structure was not reproduced by the normal Gaussian model, but by the asymmetric interface model where crosslinked polymer chains neither permeate the pore nor follow the surface roughness of the silica layer.

Journal Articles

Structure analysis of a buried interface between organic and porous inorganic layers using spin-contrast-variation neutron reflectivity

Kumada, Takayuki; Miura, Daisuke*; Akutsu, Kazuhiro*; Oishi, Kazuki*; Morikawa, Toshiaki*; Kawamura, Yukihiko*; Suzuki, Junichi*; Oku, Takayuki; Torikai, Naoya*; Niizeki, Tomotake*

Journal of Applied Crystallography, 55(5), p.1147 - 1153, 2022/10

AA2021-0903.pdf:1.06MB

 Times Cited Count:1 Percentile:31.49(Chemistry, Multidisciplinary)

Spin-contrast-variation neutron reflectivity obtains multiple reflectivity curves from a single sample and a single beam source. We used the strong point of the technique to reveal that, although methylated-perhydropolysilazane-derived silica layer has a higher porosity near the interface with acrylic urethane resin, the resin did not permeate the pore network.

Journal Articles

Development of spin-contrast-variation neutron reflectometry

Kumada, Takayuki; Akutsu, Kazuhiro*; Oishi, Kazuki*; Morikawa, Toshiaki*; Kawamura, Yukihiko*; Sahara, Masae*; Suzuki, Junichi*; Miura, Daisuke*; Torikai, Naoya*

J-PARC 20-02; J-PARC MLF Annual Report 2019, p.38 - 40, 2021/00

Journal Articles

Development of spin-contrast-variation neutron reflectometry for structural analyses of multilayer films

Kumada, Takayuki; Miura, Daisuke*; Akutsu, Kazuhiro*; Suzuki, Junichi*; Torikai, Naoya*

Hamon, 30(4), p.207 - 211, 2020/11

We developed a technique of spin-contrast-variation neutron reflectivity (SCV-NR) for structural analyses of multilayer films. The SCV-NR curves of the polystyrene monolayer film were precisely reproduced using a common set of structural parameters and neutron scattering length density at each proton polarization. This result ensures that SCV-NR curves are not deformed by inhomogeneous PH due to the spin-diffusion mechanism. The number of structural parameters of the lamellar microphase-separated poly(styrene-block-isoprene) thin film is too large to determine with a single unpolarized reflectivity curve only. However, these parameters converged through the global analysis of the SCV-NR curves. In this manner, SCV-NR determines the structure of multilayer films while excluding the incorrect structural model that accidentally accounts for a single unpolarized reflectivity curve only.

Journal Articles

Detailed structural study on the poly(vinyl alcohol) adsorption layers on a Si substrate with solvent vapor-induced swelling

Miyazaki, Tsukasa*; Miyata, Noboru*; Yoshida, Tessei*; Arima, Hiroshi*; Tsumura, Yoshihiro*; Torikai, Naoya*; Aoki, Hiroyuki; Yamamoto, Katsuhiro*; Kanaya, Toshiji*; Kawaguchi, Daisuke*; et al.

Langmuir, 36(13), p.3415 - 3424, 2020/04

 Times Cited Count:12 Percentile:59.54(Chemistry, Multidisciplinary)

Journal Articles

Development of spin-contrast-variation neutron reflectometry for the structural analysis of multilayer films

Kumada, Takayuki; Akutsu, Kazuhiro*; Oishi, Kazuki*; Morikawa, Toshiaki*; Kawamura, Yukihiko*; Sahara, Masae*; Suzuki, Junichi*; Torikai, Naoya*

Journal of Applied Crystallography, 52(5), p.1054 - 1060, 2019/10

AA2018-0116.pdf:0.86MB

 Times Cited Count:3 Percentile:33.01(Chemistry, Multidisciplinary)

We developed a technique of spin-contrast-variation neutron reflectometry (SCV-NR). Polarized-neutron reflectivity curves of film samples vary as a function of their proton-polarization P. The P-dependent reflectivity curves of a polystyrene film was precisely reproduced using a common set of structure parameters and the P-dependent neutron scattering length. The reflectivity curve of poly (styrene-block-isoprene) (PSPI) presented a shoulder attributed to holes with the depth corresponding to one period of periodic lamellae on the free surface only at a specific P. In this way, structural information about specific surfaces or interfaces can be obtained by controlling the P.

Journal Articles

Elucidation of a heterogeneous layered structure in the thickness direction of poly(vinyl alcohol) films with solvent vapor-induced swelling

Miyazaki, Tsukasa*; Miyata, Noboru*; Asada, Mitsunori*; Tsumura, Yoshihiro*; Torikai, Naoya*; Aoki, Hiroyuki; Yamamoto, Katsuhiro*; Kanaya, Toshiji*; Kawaguchi, Daisuke*; Tanaka, Keiji*

Langmuir, 35(34), p.11099 - 11107, 2019/08

 Times Cited Count:19 Percentile:68.25(Chemistry, Multidisciplinary)

Journal Articles

Materials and Life Science Experimental Facility (MLF) at the Japan Proton Accelerator Research Complex, 2; Neutron scattering instruments

Nakajima, Kenji; Kawakita, Yukinobu; Ito, Shinichi*; Abe, Jun*; Aizawa, Kazuya; Aoki, Hiroyuki; Endo, Hitoshi*; Fujita, Masaki*; Funakoshi, Kenichi*; Gong, W.*; et al.

Quantum Beam Science (Internet), 1(3), p.9_1 - 9_59, 2017/12

The neutron instruments suite, installed at the spallation neutron source of the Materials and Life Science Experimental Facility (MLF) at the Japan Proton Accelerator Research Complex (J-PARC), is reviewed. MLF has 23 neutron beam ports and 21 instruments are in operation for user programs or are under commissioning. A unique and challenging instrumental suite in MLF has been realized via combination of a high-performance neutron source, optimized for neutron scattering, and unique instruments using cutting-edge technologies. All instruments are/will serve in world-leading investigations in a broad range of fields, from fundamental physics to industrial applications. In this review, overviews, characteristic features, and typical applications of the individual instruments are mentioned.

Journal Articles

Principles of neutron reflectometry

Torikai, Naoya*; Takeda, Masayasu

Hamon, 18(4), p.221 - 227, 2008/10

Neutron reflectometry is a non-destructive structural analysis method utilizing optical property of neutron at interfaces between two media, and is indispensable for structural analysis on material interfaces due to high depth resolution of a sub-nm scale. The specular reflection of neutron at the interface can be described by the Shr$"{o}$dinger equation with the one-dimensional square well potential for a plane wave. Here, the principles of neutron reflectometry are explained using a typical few examples from a single ideal interface to a multi-layer system.

Journal Articles

Buried H monolayer at hetero-interface between highly mismatched Sr films and Si substrates

Yamazaki, Tatsuya; Asaoka, Hidehito; Takeda, Masayasu; Yamazaki, Dai; Taguchi, Tomitsugu; Torikai, Naoya*; Toyoshima, Yasutake*; Shamoto, Shinichi

Transactions of the Materials Research Society of Japan, 33(3), p.611 - 614, 2008/09

Strontium and SrO are well-known templates on Si for SrTiO$$_{3}$$, highly-desirable transistor gate material. When stacked on Si, Srlayer becomes amorphous due to its large lattice mismatch of 12%. By introducing a monatomic hydrogen layer on Si, we succeeded in making the Sr (and subsequent SrO) layer(s) grow epitaxially with atomically abrupt interface. However, it is some what mysterious how the monatomic hydrogen layer behaves to manage this large mismatch. In order to identify its behavior, we have employed compound analysis by neutron reflectometer as well as multiple-internal-reflection fourier-transform infrared spectroscopy (MIR-FTIR) to investigate the buried heterointerface of Sr grown on Si(111)1$$times$$1: monohydride. We have found difference between the H- and D-terminated substrates in the reflectivity profiles, and changes in Si-H bonding features with the Sr growth (mainly at the initial monolayer stage) in the FTIR spectra. From these, existence of buried H layer at the heterointerfaceis confirmed with its bonding environment.

Journal Articles

Exchange bias and uncompensated spins in a Fe/Cr(100) bilayer

Kim, K. Y.*; Hwang, Y. S.*; Park, J.-G.*; Torikai, Naoya*; Takeda, Masayasu; Han, S. W.*; Shin, S. C.*

Physica Status Solidi (B), 244(12), p.4499 - 4502, 2007/12

 Times Cited Count:1 Percentile:6.71(Physics, Condensed Matter)

We have investigated the effect of the field cooling on the exchange bias and the coercivity in an exchange-biased Fe/Cr(100) bilayer using SQUID magnetometer. After the field cooling, magnetization shifted upwards, indicative of surplus magnetic moments, which could be interpreted as an evidence of pinned and uncompensated Cr magnetic moments induced by the cooling field. Interestingly enough, we also discovered that not all the pinned and uncompensated spins seem to be involved in producing the exchange bias, although they contribute to increasing the coercivity and inducing the surplus magnetization.

Journal Articles

Resonance spin-echo option on neutron reflectometers for the study of dynamics of surfaces and interfaces

Yamazaki, Dai; Soyama, Kazuhiko; Ebisawa, Toru*; Takeda, Masayasu; Torikai, Naoya*; Tasaki, Seiji*; Matsuoka, Hideki*

Physica B; Condensed Matter, 356(1-4), p.229 - 233, 2005/02

 Times Cited Count:1 Percentile:6.25(Physics, Condensed Matter)

The application of neutron reflectometry to study dynamic phenomena at surface and interfaces have been restricted so far. It was mainly due to the low intensity of neutron sources, but now high-intensity spallation neutron sources are under construction in Japan (J-PARC) and U.S. (SNS). We have a plan to install a spin-echo option on the J-PARC neutron reflectometer with horizontal sample geometry for studies on dynamics of surfaces and interfaces. This option is based on the resonance spin-echo method and aimed at dynamics upto hundreds of nanoseconds. In this contribution, the plan and status of development are introduced together with the principle and characteristics of this option.

Journal Articles

Recent activities and progress on PORE reflectometer

Takeda, Masayasu; Torikai, Naoya*; Ino, Takashi*; Tasaki, Seiji*

KENS Report-XIV, p.205 - 206, 2003/00

no abstracts in English

Journal Articles

A Neutron reflectometer installed at the cold neutron triple-axis spectrometer (LTAS,C2-1) in JRR-3M

Soyama, Kazuhiko; Metoki, Naoto; Minakawa, Nobuaki; Morii, Yukio; *; *

Journal of the Physical Society of Japan, 65(A), p.133 - 135, 1996/00

no abstracts in English

Journal Articles

Neutron reflectometer (C3-1-2) at the JRR-3M reactor at JAERI

Ebisawa, Toru*; Tasaki, Seiji*; *; *; Soyama, Kazuhiko; *; *

Physica B; Condensed Matter, 213-214, p.901 - 903, 1995/00

 Times Cited Count:37 Percentile:86.08(Physics, Condensed Matter)

no abstracts in English

Oral presentation

Future prospects of neutron reflectometry in Japan

Takeda, Masayasu; Yamazaki, Dai; Soyama, Kazuhiko; Torikai, Naoya*

no journal, , 

no abstracts in English

Oral presentation

Buried hetero-interface of H, D monolayer

Asaoka, Hidehito; Takeda, Masayasu; Soyama, Kazuhiko; Shamoto, Shinichi; Yamazaki, Tatsuya; Torikai, Naoya*

no journal, , 

no abstracts in English

Oral presentation

Neutron reflectivity study on buried hetero-interfacial structure of H, D monolayer

Asaoka, Hidehito; Takeda, Masayasu; Yamazaki, Dai; Yamazaki, Tatsuya; Taguchi, Tomitsugu; Shamoto, Shinichi; Torikai, Naoya*

no journal, , 

no abstracts in English

Oral presentation

Development of dynamic nuclear polarization system for neutron reflectivity measurement

Kumada, Takayuki; Akutsu, Kazuhiro*; Oishi, Kazuki*; Morikawa, Toshiaki*; Kawamura, Yukihiko*; Suzuki, Junichi*; Torikai, Naoya*

no journal, , 

Scattering power of neutrons against protons depends remarkably on relative directions of their spins. So, polarized neutron scattering profiles vary as a function of proton polarization of measuring specimen. We can extract fruitful structural information from these profiles. This technique named "spin-contrast variation" has been used to study meso-scale bulk structure using small-angle neutron scattering. Now, we plan to apply the spin-contrast variation technique to study surface structure using neutron reflectivity measurements. The spin-contrast neutron reflectivity measurement will determine surface structure of complex soft materials such as adhesives.

Oral presentation

Development of dynamic nuclear polarization system for neutron reflectrometry

Kumada, Takayuki; Akutsu, Kazuhiro*; Oishi, Kazuki*; Morikawa, Toshiaki*; Kawamura, Yukihiko*; Suzuki, Junichi*; Torikai, Naoya*

no journal, , 

no abstracts in English

27 (Records 1-20 displayed on this page)