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.

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

https://doi.org/10.5611/hamon.30.4_207

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.

Thermal stability of a magnetic domain wall in nanowires

Fukami, Shunsuke*; Ieda, Junichi; Ohno, Hideo*

Physical Review B, 91(23), p.235401_1 - 235401_7, 2015/06

https://doi.org/10.1103/PhysRevB.91.235401

We study thermal stability of a magnetic domain wall pinned in nanowires made of Co/Ni multilayers, and analyze the effective volume that governs the thermal stability. We find that, above a critical wire width, the domain wall depinning is initiated by a subvolume excitation and that the critical width is dependent on the wire thickness. The obtained findings are supported by the distribution of critical current density for domain wall depinning and are qualitatively described by considering the balance between the Zeeman energy and domain wall elastic energy.

Development of multilayer mirrors for use in the wavelength region of 4 nm

Ishino, Masahiko; Yoda, Osamu*; Koike, Masato

JAERI-Research 2005-019, 13 Pages, 2005/09

JAERI-Research-2005-019.pdf:1.46MB

We have developed soft X-ray multilayer mirrors for use around the wavelength region of 4 nm including the K-absorption edge of carbon (). We have chosen CoO and Cr as the final candidate materials for absorber layers, and SiO and Sc for the spacer materials as the result of theoretical invitation. CoO/SiO, CoO/Sc and Cr/Sc multilayer mirrors have been fabricated by means of an ion beam sputtering (IBS) method. As the result of structure evaluations with X-ray diffraction measurement, we have found that the fabricated CoO/Sc and Cr/Sc multilayer mirrors have stable structures. Soft X-ray reflectivity measurements for fabricated multilayer mirrors are carried out in the wavelength region of 4 nm with a synchrotron radiation source. We have found that the Cr/Sc multilayer mirror has a high soft X-ray reflectivity. However, soft X-ray reflectivities below the absorption edge of carbon are reduced. The analyses obtained by EPMA and SIMS suggested that this phenomenon was attributed to contamination of carbon.

Soft X-ray magnetic circular dichroism study of [Co/Pd] multilayered perpendicular magnetic films

Agui, Akane; Mizumaki, Masaichiro*; Matsushita, Tomohiro*; Asahi, Toru*; Kawaji, Jun*; Sayama, Junichi*; Osaka, Tetsuya*

Journal of Applied Physics, 95(12), p.7825 - 7831, 2004/06

https://doi.org/10.1063/1.1738535

The electronic and spin states of [Co/Pd] multilayered perpendicular magnetization films with various seedlayers have been investigated by means of soft X-ray absorption and magnetic circular dichroism spectroscopy at the Co -edges. The expectation values of the orbital angular momentum and the spin angular momentum of Co atom in the [Co/Pd] multilayered film were estimated using the sum rule. It was found that the seedlayer changes macroscopic magnetic properties of the [Co/Pd] multilayered film without affecting the electronic and spin states of the upper layers of Co.

Heat stability of Mo/Si multilayers inserted with compound layers

Ishino, Masahiko; Yoda, Osamu; Takenaka, Hisataka*; Sano, Kazuo*; Koike, Masato

Surface & Coatings Technology, 169-170(1-3), p.628 - 631, 2003/06

no abstracts in English

Heat stability of Mo/Si multilayers inserted with silicon oxide layers

Ishino, Masahiko; Yoda, Osamu; Sano, Kazuo*; Koike, Masato

X-Ray Mirrors, Crystals, and Multilayers II (Proceedings of SPIE Vol.4782), p.277 - 284, 2002/12

no abstracts in English

New type of Monk-Gillieson monochromator capable of covering a 0.7- to 25-nm range

Koike, Masato; Sano, Kazuo*; Harada, Yoshihisa*; Yoda, Osamu; Ishino, Masahiko; Tamura, Keisuke*; Yamashita, Kojun*; Moriya, Naoji*; Sasai, Hiroyuki*; Jinno, Masafumi*; et al.

X-Ray Mirrors, Crystals, and Multilayers II (Proceedings of SPIE Vol.4782), p.300 - 307, 2002/07

For the purpose of realizing an evaluation beamline for characterizing soft X-ray optical elements in a wide wavelength range of 0.7-25 nm, we have designed and constructed a new type of monochromator that combined two types of Monk-Gillieson monochromators. One is a conventional type equipped with three varied-line-spacing plane gratings, allowing a choice of two included angles. The other is a new type that employs a scanning mechanism based on Surface Normal Rotation (SNR). The SNR scheme provides high throughput at short wavelengths and simple scanning mechanism by means of a grating rotation about its normal. The monochromator is operated in the SNR and conventional modes over the ranges of 0.7-2.0 nm and 2.0-25 nm, respectively. In this paper we describe the optical and mechanical designs of the monochromator, wavelength calibrations in the SNR mode, and preliminary experimental data, such as the transmittance of an Al filter at 0.8 nm and the total yield photoelectron measurement on a MgO powder in a wavelength rage of 0.7-2 nm.

Boundary structure of Mo/Si multilayers for soft X-ray mirrors

Ishino, Masahiko; Yoda, Osamu; Haishi, Yasuyuki*; Arimoto, Fumiko*; Takeda, Mitsuhiro*; Watanabe, Seiichi*; Onuki, Somei*; Abe, Hiroaki

Japanese Journal of Applied Physics, Part 1, 41(5A), p.3052 - 3056, 2002/05

https://doi.org/10.1143/JJAP.41.3052

no abstracts in English

Evaluation methods of interlayer-structure-distribution in multilayers by total-electron-yield X-ray standing wave measurements

Muramatsu, Yasuji; Takenaka, Hisataka*; Gullikson, E. M.*; Perera, R. C. C.*

Advances in X-Ray Chemical Analysis, Japan, 33, p.145 - 154, 2002/00

no abstracts in English