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次世代放射光施設で建設中の RIXS ビームラインの光学設計について発表 する。, 14th International Conference on Synchrotron Radiation Instrumentation

次世代放射光施設で QST が第 1 期に整備される 3 本の共用ビームラインのうち、BL06U では軟 X 線ナノ光電子分光ビームラインとして、ナノ集光ビームを用いたスピン分解角度分解光電子分光（ARPES）を実現することを計画している。次世代放射光施設利用研究検討委員会ビームラインワーキンググループによって纏められた要求仕様に基づいて現在設計を進めているビームライン光学系について報告する。, 14th International Conference on Synchrotron Radiation Instrumentation

軟X線ナノ光電子分光（ARPES）ビームラインは、50–1,000 eVの軟X線を高精度ミラーを用いてナノ集光化し、高効率かつ多自由度のナノ集光ARPES計測を実現することを目指している。本ビームラインでは、高エネルギー分解能と極限集光を両立するためにcPGMを採用し、M1で平行化した放射光をM3振り分け鏡で再度集光して各ブランチビームラインに導く構成となっている。A/Bブランチではナノ集光ARPESステーションとマイクロ集光ARPESステーションを排他的に利用する計画である。講演ではエンドステーションの仕様も含めた最新の検討状況について報告する。, 第35回日本放射光学会年会・放射光科学合同シンポジウム

次世代放射光施設で建設中のRIXSビームライン、エンドステーションの検討状況について発表する。, 第35回日本放射光学会年会・放射光科学合同シンポジウム

顕微スピントロニクスビームラインは、2024年から供用開始を予定している次世代放射光施設において、QSTが初期に整備する３本のビームラインのうちの１本として計画されている。伝統的な磁性材料のみならず、近年の原子層薄膜やトポロジカル物質等の発見・開発や、電流に限らないスピンを介した多様なエネルギー変換機構の構想などにより、磁性・スピントロニクス分野の研究は近年一層の活況を呈している。本ビームラインはこれらの新奇スピン物性の研究をさらに加速発展させるために、次世代放射光施設の低エミッタンス光源を活かした顕微スピン分光(X線磁気円・線二色性分光)測定を実現して、広範な試料に対して提供することを目標としている。光源には分割型APPLE-IIアンジュレータを採用して軟XからテンダーX線までの広い波長範囲と自由度の高い偏光制御を両立し、モノリシックウォルター鏡を利用したサブミクロン集光系やフレネルゾーンプレートを用いたナノ集光系等の目的に応じた空間分解能を持つ複数の顕微スピン分光エンドステーションに放射光を提供する光学系およびエンドステーション自体の設計を進めている。 講演ではエンドステーションの仕様も含めた最新の検討状況について報告する。, 第35回日本放射光学会年会・放射光科学合同シンポジウム

The beamline for angle-resolved photoemission spectroscopy (ARPES) with a nano-focused beam (nano-ARPES) is planned as one of the public beamlines in NanoTerasu, the 3-GeV next-generation synchrotron radiation facility at Tohoku, Japan, which is scheduled to start operation in 2024. A 4 m long APPLE-II type undulator provides brilliant soft X-rays with various polarizations (linear horizontal and vertical, and left and right circular) in the energy range of 50-1,000 eV. A collimated plane grating monochromator is adopted as a soft X-ray monochromator because we can select the demagnification factor of grating cf f = cosα/cosβ between the high energy-resolution (HR) mode for HR-ARPES experiments and the low divergence mode for high-flux nano-ARPES measurements. This beamline aims to produce the high flux nano-focused beam by using ultrahigh precision reflective mirror optics, not a Fresnel zone plate used as a focusing optics in the previous nano-ARPES station at other synchrotron facilities.

A synchrotron radiation beamline in the soft- and tender-X ray energy range of 180-3000 eV with versatile polarization control has been designed for NanoTerasu, the 3-GeV next-generation synchrotron radiation facility at Tohoku, Japan. A series of four APPLE-II type undulators is adopted as a photon source to realize the required beam properties with high-speed polarization switching. The beamline optics is designed for a highly efficient and precise use of x-ray magnetic circular/linear dichroism (XMCD/XMLD) technique balancing high photon flux and energy resolution. The simulated performance of the segmented undulator together with the monochromator optics achieved the sufficiently high flux and energy resolution (E/ΔE) in whole target energy range. Two endstations with the different re-focus optics, one for marginal spot size with high flux and the other for ultimate focus down to ∼10 nm are also designed. The simulated performance of the beamline encourages the future researches of high-throughput and nm-focused spintronic measurements.

The optical design of the ultrahigh-resolution RIXS beamline, which is currently developed at NanoTerasu in Japan, is described. The main goal of this beamline is to perform ultrahigh-resolution RIXS measurements with a total energy resolution of E/ΔE>150,000 for both beamline and RIXS spectrometer. To achieve the ultra-high resolution, a 2D-RIXS spectrometer using energy-dispersive X-ray is employed to compensate for lower throughput at higher energy resolution, and the optics of the beamline is optimized for the 2D-RIXS spectrometer. A vertically dispersing in-focus variable-included-angle varied-line-spacing plane grating monochromator is employed for the beamline, with an entrance slit to ensure the ultrahigh resolution. First and second mirrors focus X-ray on entrance slits vertically and horizontally, respectively, and the divergent X-ray is irradiated onto the grating. For the 2D-RIXS spectrometer, there is no exit slit, and the vertically energy-dispersed X-ray is irradiated directly onto a sample. In front of the sample, X-ray is horizontally refocused by a Wolter type-I mirror. The expected horizontal focus size at the sample is ~0.7 μm. The expected photon flux is ~1×1011 photons/s at 500–1000 eV with a virtual slit width of 2 μm required for E/ΔE>150,000. The height of the dispersed X-ray available in the 2D-RIXS spectrometer is ~120 μm, which allows the use of a remarkably high flux of ~6×1012 photons/s, and the beamline will serve as an ultrahigh-resolution and high-efficiency RIXS facility.

Tb-Co perpendicular magnetization films are mother materials for perpendicular magnetic recording media. Since the magnetic recording technique is based on magnetic switching of a material, investigating a magnetic the response of the material to a magnetic field is important. The magnetic response of the entire system is the net of each microscopic response of the spin magnetic moment and orbital magnetic moment of the elements. Herein we study the magnetization processes of the spin, orbital, and the element-specific magnetic moments by measuring the magnetic field dependence of the magnetic Compton profile of a Tb12Co88 film. The spin and orbital magnetic moments have opposite orientations. Similarly, Tb and Co magnetic moments have opposite directions. When the total magnetic moment reverses, the orientation of spin and orbital magnetization as well as Tb and Co reverse. Decreasing the temperature, the fluctuation of the magnetic moment of Tb in the perpendicular direction decreases. So the cancelation between the Tb and Co moments reduces total magnetic moment.

本ビームライン（BL）は、2024年度に供用開始予定の次世代放射光施設共用の一つで、X線磁気円二色性等の軟X線ナノ吸収分光を用いて磁性・スピントロニクス材料・デバイスにおける磁気構造、ダイナミクス等の学理解明に供することを目的とする。分割型APPLEアンジュレータによって軟X線からテンダーX線まで幅広い帯域における偏光光源を生成でき、かつ発光点の位置変化を伴わずに偏光制御できることが最大の特長で、そのような優れた特長をいかせるBL光学系の設計の検討を開始した。講演では検討状況とその結果について報告する。, 第34回日本放射光学会年会・放射光科学合同シンポジウム

軟X線超高分解能共鳴非弾性散乱(RIXS)ビームラインの光学設計の検討状況について報告する。, 第34回日本放射光学会年会 放射光科学合同シンポジウム

軟X線ナノ光電⼦分光（ARPES）ビームラインは、2024年から供⽤開始を予定している次世代放射光施設において、QSTが初期に整備する3本の共⽤ビームラインのうちの1本として計画されている。本ビームラインの⽬標は、軟X線ナノ集光素⼦としてWolterミラーを採⽤して⾼フラックスのナノ集光ビームを⽣成すると共に、多チャンネルのスピン検出器を採⽤して⾼効率化を達成し、世界に先駆けてナノ集光スピン分解ARPES計測を実現することにある。ビームラインの仕様については、これまで に次世代放射光施設利⽤研究検討委員会ビームラインワーキンググループの中で議論された。ここで要求されたスペックを満たすためのビームライン光学系の検討を現在進めており、講演ではその検討状況について報告する。, 第34回日本放射光学会年会・放射光科学合同シンポジウム

The valence distribution and local structure of Bi1–xPbxNiO3 (x ≤ 0.25) were investigated by comprehensive studies of Rietveld analysis of synchrotron X-ray diffraction (SXRD) data, X-ray absorption spectroscopy (XAS), hard X-ray photoemission spectroscopy (HAXPES), and pair distribution function (PDF) analysis of synchrotron X-ray total scattering data. Disproportionation of Bi ions into Bi3+ and Bi5+ was observed for all the samples, but it was a long-ranged one with distinct crystallographic sites in the P1 triclinic structure for x ≤ 0.15, while the ordering was short-ranged for x = 0.20 and 0.25. An intermetallic charge transfer between Bi5+ and Ni2+, leading to large volume shrinkage, was observed for all the samples upon heating at ∼500 K.

We investigated the magnetization process of Fe (110) film using the field dependence of magnetic Compton scattering and M\"ossbauer spectroscopy. From the magnetic Compton profiles, the spin and orbital magnetic moment specific magnetization versus magnetizing field curves were obtained. From the M\"ossbauer spectra, the angles between the magnetizing field and the magnetic moment were obtained. It was found that the magnetizing field dependence of the ratio between orbital moment and spin moment was related to the angles between the magnetizing field and the magnetic moment. We indicate that the magnetic field dependence of the orbital magnetic moment plays a role in the magnetization process., 本研究では磁気コンプトン散乱およびメスバーワー分光を用いてFe薄膜の磁化過程を詳細に調べた。磁気コンプトン散乱からスピン磁気モーメントと軌道磁気モーメントの磁化曲線を算出した。メスバーワースペクトルからは磁化と外部磁場のなす角の印加磁場依存性を調べた。これにより磁化曲線の振る舞いは磁化と外部磁場のなす角の変化と大きなかかわりがあることが分かった。

While the charge transfer between the transition metal and oxygen sites in transition metal oxides has been studied by resonant inelastic soft X-ray scattering, the charge transfer between transition metal sites has not been studied as of yet. In this study, we have measured the Ti 2p edge resonant inelastic X-ray scattering spectra of MTiO3 (M = Mn, Fe, Co, and Ni) in order to investigate the intermetallic M 3d–Ti 3d charge transfer. We found the peak around −4.5 eV in the energy loss scale for all MTiO3, which is attributed to the M 3d–Ti 3d charge transfer; whereas only FeTiO3 exhibits an additional intermetallic charge transfer peak at −2.5 eV. We attributed that the existence of the additional peak in FeTiO3 reflects the relation of M 3d and Ti 3d energy levels.

The charge ordering of Fe 2+ and Fe 3+ ions in LuFe 2 O 4 induces ferroelectricity below 330 K. In this study, the X-ray absorption spectra (XAS) at the Fe L 2,3 -edge are investigated to study charge ordered- and disordered-states. The polarization dependence of XAS revealed that the energy level of ( d xy , d x 2– y 2 ) is lower than that of ( d yz , d zx ). In the charge-ordered state, the Fe L 3 -XAS shows a double-peak structure, which is a characteristic of Fe 2+ and Fe 3+ ions. In the high-temperature region, the double-peak structure becomes a broad single peak, because of overlap with the thermally excited state.

Charge transfer is a key concept in understanding X-ray spectra of transition metal oxides. In this study, X-ray absorption spectra (XAS) and X-ray emission spectra (XES) at the O 1 s -edge of MTiO 3 (ilmenite: M = Mn, Fe, Co, and Ni) have been measured. It was found that the O 1 s -edge XES show the existence of not only oxygen–metal charge transfer but also intermetallic charger transfer. Moreover, the band gap of each ilmenite was evaluated to be 2.4–2.8 eV by measuring the distance between the spectra edges of XAS and XES.

Chemical evolution in glycilglycine (Gly2) films irradiated with 146 nm vacuum ultraviolet light was studied. It is found that quantum efficiency of chemical evolution from Gly2 to glycilglycilglycine (Gly3) is smaller than that to glycilglycilglycilglycine (Gly4) due to the multiple step of reaction. Furthermore, we have carried out measurement of soft X-ray natural circular dichroism spectra for serine and alanine films in the energy region of oxygen 1s transition and we report the splitting of 1s→ π * transitions.

A-site-ordered perovskites LaMn(3)Cr(4)O(12) and LaMn(3)Ti(4)O(12) were synthesized under high-pressure and high-temperature conditions. The charge formula of LaMn(3)Cr(4)O(12) was found to be LaMn(3+)(3)Cr(3+)(4)O(12) with Mn(3+) at the square-coordinated A site. The valence of the A-site Mn ions in LaMn(3)Ti(4)O(12) appeared to be less than +2, and the charge combination in this compound seemed to be LaMn(1.67+)(3)Ti(4+)(4)O(12). Although the square-coordinated A site in A-site-ordered perovskites has been widely known to be occupied by Jahn-Teller active Mn(3+), the present results show that the valence of Mn at the A site can vary from +3 to possible +1.67.

We have carried out X-ray absorption measurements with its magnetic circular dichroism (MCD) of perpendicular magnetic films of DyxCo100−x (15⩽x⩽33) at Dy M4,5 and Co L2,3 absorption edges to investigate electronic and spin states of the Dy 4f and Co 3d states, respectively. The replacement of major spin between Dy 4f and Co3d is clearly observed in the spectra between 20⩽x⩽25. The expected values of the orbital angular moment ∣〈Lz〉∣ of Dy 4f were estimated to be 1.4–0.8 μB while that of Co 3d was estimated to be around 0.2 μB.

A metal to insulator transition in integer or half integer charge systems can be regarded as crystallization of charges. The insulating state tends to have a glassy nature when randomness or geometrical frustration exists. We report that the charge glass state is realized in a perovskite compound PbCrO3, which has been known for almost 50 years, without any obvious inhomogeneity or triangular arrangement in the charge system. PbCrO3 has a valence state of Pb(2+)(0.5)Pb(4+)(0.5)Cr(3+)O3 with Pb(2+)-Pb(4+) correlation length of three lattice-spacings at ambient condition. A pressure induced melting of charge glass and simultaneous Pb-Cr charge transfer causes an insulator to metal transition and ∼10% volume collapse.

We studied microscopic magnetic properties of each consistent atom in boron added CoNiFe electroless-deposited soft magnetic films, which is a promising candidate for the soft magnetic underlayer of the perpendicular magnetic recording medium, by X-ray absorption spectra (XAS) and magnetic circular dichroism (MCD) measurement. It was found that various monoxides and Fe sesquioxide coexisted with the metals at the upper part of the films. The results of MCD sum rule showed the expected values of orbital angular moment 〈Lz〉 for the film with macroscopic magnetic domain boundaries were larger than those of without domains at Co and Ni atoms and smaller at Fe atom. The appearance of macroscopic magnetic domain boundaries probably originated from the increase in 〈Lz〉 of Co and/or Ni atoms. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

The soft x-ray absorption and magnetic circular dichroism spectra at the Co L2,3-edges of [Co/Pd]20 and [CoB/Pd]20 multilayered films, which were sputter-deposited in Ar gas containing N2 at room temperature, were measured to investigate the electronic and spin states of the films. The macroscopic magnetic properties, such as coercivity and saturation magnetization, and microstructural properties, such as grain size and preferred orientation, were markedly changed for the [Co/Pd]20 film by the B doping and N2 addition. The B doping and/or the addition of N2 gas caused appreciable changes not only in macroscopic magnetic properties but also in microscopic properties, such as the spin angular momentum and orbital angular momentum, throughout the multilayered film. On the other hand, a new spectral feature at the high energy side of the Co L3-edge peak in x-ray absorption spectra was found in only the films with N2 added. Thus, the microscopic properties, such as electronic and spin states, of the Co 3d electronic state for the [Co/Pd]20 and [CoB/Pd]20 films were changed by only the sputtering process with additive N2 gas.

X-ray absorption and magnetic circular dichroism spectra (XAS–MCD) of the Dy M 4,5 -edges of Dy x Co 100− x ( x = 15–33) thin films are measured. The advantage of element and orbital selectivity in the XAS–MCD measurements enables us to directly observe the magnetic moments of specified elements. The MCD intensity at the Dy M 5 -edge is maximum when the incident X-ray is normal to the surface and the incident angle dependence of the MCD intensity shows a sine curve. That gives us information about the angular distribution of the Dy magnetic moments with respect to the total magnetization direction and the opening angle of the cone. Applying the sum rule, the expectation value of orbital magnetic moment was estimated. The half opening angle of the random distribution of the moments were estimated and it was found that the angle has its minimum value around x = 20.

Intra-versus inter-site electronic excitations in NdNiO3 by resonant inelastic ultra-soft X-ray scattering at Ni 3p edge

We propose a new algorithm based on the scattering pattern matrix and the maximum entropy method to achieve a very precise investigation of the three-dimensional atomic nucleus positions in material by the electron holography technique. The forward scattering problems, i.e. strong intensity of forward focusing peak, and frequency shift in the forward scattering region, are solved in this algorithm, since the forward scattering effects are almost perfectly taken into account. We applied the algorithm to an experimental single-energy hologram of Si 2s photoemission with kinetic energy Ek = 1110.3 eV from a Si(001) single-crystal surface and succeeded in reconstructing the atomic nucleus positions of the Si bulk structure. The reconstructed space size is about 800 picometers, and as many as 21 atoms are recognized. The accuracy of the position for most atoms is within 50 picometers.

Resonant Mn L α,β soft X-ray emission spectra of a colossal magnetoresistive manganese oxide La 1.2 Sr 1.8 Mn 2 O 7 have been measured at the Mn L 2,3 -edges excited by monochromatized undulator radiation. The excitation energy dependence of the spectra has been analyzed in terms of d – d and charge-transfer excitations. The experimental spectra are reproduced by the multiplet calculation for the Mn 3+ configuration, which is consistent with the dominant occupancy of the 3 d x 2 - y 2 orbital and probably a phase separation.

Soft X-ray induced chemical evolution from glycine (Gly) to glycyl–glycine (glycine dimer or Gly–Gly) was studied for sublimated films of Gly. Values of quantum yield of Gly dimer formation were determined by high performance liquid chromatography (HPLC) technique to be: (1.2 ± 0.2) × 10 −1 for 400 eV, (4.6 ± 0.5) × 10 −2 for 407 eV and (3.2 ± 1.5) × 10 −2 for 860 eV irradiation, respectively. We measured X-ray absorption spectra of irradiated Gly films at near edge region of nitrogen K-edge, as a function of X-ray dose. Formation of Gly–Gly was confirmed by the appearance and growth of 402 eV peak, which is a fingerprint of the peptide bond. The important role of surface to chemical evolution is discussed.

The O Kα soft X-ray emission and absorption spectra (XES and XAS) of La 1.2 Sr 1.8 Mn 2 O 7 were measured at selected excitation energies using synchrotron radiation in order to investigate the electronic structure. The dependence of O Kα XES on excitation energy was observed. It is attributed to the 2p partial density of states of inequivalent oxygen sites. It was found that O(1) atom makes Mn 3d 3 z 2 − r 2 orbital stable.

Magnetron-sputtered carbon nitride thin films with different structures and compositions were analyzed by X-ray and ultraviolet photoelectron spectroscopy (XPS and UPS), near-edge X-ray absorption ...

The electronic structure of Eu 1− x Dy x TiO 3 is investigated by means of soft X-ray absorption spectroscopy (XAS) near the Ti L 2,3 -edges. The spectrum of EuTiO 3 shows a satellite structure in the high-energy side of four main peaks. The spectra analyzed by using a full-multiplet calculation and the observed features are almost reproduced by the cluster model. The satellite structure above four main peaks is due to the charge transfer (CT) from the O 2 p orbital to the Ti 3 d orbital. The intensity decreases with the composition of Dy. This tendency corresponds to the change of conductivity against x . This result means that the intensity of the charge transfer peak is strongly related to the conductivity in Eu 1− x Dy x TiO 3 . The charge transfer from the O 2 p orbital to the Ti 3 d orbital plays an important role in the conductivity in EuTiO 3 . According to the values of the parameters (charge transfer Δ, Coulomb interactions U dd , U dc ) obtained by the theoretical calculation, EuTiO 3 is an intermediate between the Mott-Hubbard-type and Charge-Transfer-type insulator.

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 L2,3-edges. The expectation values of the orbital angular momentum 〈Lz〉 and the spin angular momentum 〈Sz〉 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.

A "scattering pattern matrix" method is proposed here to overcome the difficulties presented by photoelectron holography, such as forward-scattering and multi-energy problems. This method makes it possible to reconstruct a three-dimensional atomic arrangement from a single-energy hologram. We have utilized the "scattering pattern matrix" that includes the angular variation of the scattered object waves, and we have adopted a special average process and the gradient projection method for minimizing the mean-squared error. The reconstruction of the Si bulk structure is demonstrated by using an experimental Si(111) 2s single-energy hologram. The holographic reconstruction provided a three-dimensional image with a size of 10 A along both the vertical and horizontal axes.

The electronic and spin states of the perpendicular magnetization films of Tb17 Feχ Co (83-χ_) (χ=0, 9.5, 32.5, 61.4 and 74.5) were measured by means of soft Χ-ray absorption and magnetic circular dichroism spectroscopy for Tb element to investigate the magnetic anisotropy. The origin of the magnetic anisotropy is said to be caused by a large orbital moment of the well-localized 4ƒ electron. The expectation values of orbital moment for the different composition of Fe were estimated to be about 1.2 μB applying a sum rule for the spectra. Using a theoretical model calculation the opening angle of the conical distribution of Tb moment along the easy axis of magnetization was estimated to be about 67 degree.

The photoion yields from O+ to O2+ were measured in the 1s–2p autoionizing resonance region of the 525–540 eV photon energy range. A multiconfiguration Dirac–Fock calculation was performed to interpret the experimental data and the results show fairly good agreement with the experimental ones. Photoionization of the N-like isoelectronic sequences of O+ and Ne3+ are discussed.

Magnetic circular dichroism (MCD) spectra of CrFe 2 O 4 have been measured by using the helicity switching method. The method achieves a high signal-to-noise ratio and resolved the fine structure in these spectra. The theoretical spectra, which were calculated by the charge transfer model, reproduced the experimental spectra. The origin of three negative peaks around the L3 edge in Cr 2p-MCD is attributed to the [Formula: see text] electron configuration in the initial state.

We have performed Co 2p X-ray absorption spectroscopy (XAS) on a mixed valence hexagonal layered system NaCo 2 O 4, which shows large thermopower and metallic conductivity. We also measured XAS for SrCoO 3 and LaCoO 3 as examples of typical Co ionic states. The Co ions of the last two materials are octahedrally surrounded by oxygen atoms. A Co atom in NaCo 2 O 4 also has octahedral coordination with oxygen atoms but it is distorted slightly. The Co ions in SrCoO 3 and LaCoO 3 are in the d5 and d6 configuration respectively. The spectrum of NaCo 2 O 4 resembles that of LaCoO 3 rather than that of SrCoO 3; the Co ions in NaCo 2 O 4 can be regarded as the d6 configuration. Also, we have tried to calculate the XAS spectra by using the charge-transfer multiplet model (CT-M). Although we could not find out the best-fitting parameters, the results suggested the itinerancy of the Co 3d states.

An understanding of the microscopic processes underlying the magnetization of the thin films is essential to the design and development of efficient magnetic recording media. In this context, we measure the magnetic Compton profile (MCP) of Tb x Co100−x films (13 x 20) and investigate the microscopic (spin magnetic moment (), orbital magnetic moment (), and element specific magnetic moment ( and )) magnetization processes. Using the magnetic-field dependence of MCP, we obtain the spin- and orbital-specific magnetization curves (SSMH and OSMH, respectively). From the profile-fitting analysis, we also obtain the element specific SSMH curves, and we find from our results that the ratio is nearly constant. Thus, it is assumed that the magnetic switching processes of and cooperatively occur in this system (corresponding to and ). In addition, we observe that and are −1 at x 17. This implies that the magnetic moment of Tb aligns toward the magnetic field in the region of x > 17 and that of Co aligns toward the magnetic field in the region of x < 17. We estimate that this value of x 17 is the compositional point that corresponds to the compensation composition of Tb and Co.

The present performance of a soft X-ray beamline BL23SU at SPring-8 is described. The resolving power realized on a varied-line-spacing plane grating monochromator connected to a variably polarizing undulator was estimated to be better than 10 000 at 400 eV and ∼6500 at 867 eV. In addition, reasonable photon flux of more than 1011 photons/s/100 mA/0.02% b.w. is available in the energy range of 0.5–1.8 keV at experimental stations.

This article presents the first operation of the magnetic circular dichroism (MCD) measurement system with periodic photon-helicity switching. The measurements were performed at the newly constructed soft x-ray beamline—BL23SU— at the third-generation synchrotron radiation facility, SPring-8. The monochromator control system was synchronized to the movement of the magnetic row (phase shift) of an APPLE-2 (Sasaki) type variably polarizing undulator. The periodic phase shift of the undulator provided the switching of helicity polarizing soft x rays up to 0.1 Hz. The closed-orbit distortion of the storage ring was controlled to avoid optical axis disturbances at this beamline as well as at other beamlines. The circular dichroism spectra with helicity switching by APPLE-2 show the possibility of high-sensitivity MCD measurements. This method promotes precise MCD measurements and can be a powerful technique to study magnetism as well as dichroism.

Recently, we have developed a synchronous SR beam position diagnostic system. In this system, more than one X-ray beam position monitor is used synchronously and an oscillation of the SR beam position all through the storage ring can be detected. For an example, during the high speed driving of the insertion device, beam oscillation and shift can be simultaneously observed at different beamlines. To start the measurements simultaneously at the different beamlines, a trigger signal was conveyed by a cordless telephone. This paper describes the system and performance tests of it.

The electronic structure of CuGeO3 has been studied using soft X-ray absorption and emission spectroscopy. The unoccupied and occupied valence states are reflected by O 1s absorption and OK alpha emission spectra, respectively. An absorption pre-peak appe

Resonant soft X-ray emission spectra have been measured at the Ni 2p edge of a planar nickel complex K2Ni(CN)4·H2O and interpreted by performing ab initio configuration interaction calculations. This cyano complex shows characteristic metal-to-ligand charge transfer (MLCT) bands in the Ni 2p photoabsorption spectra. Resonant soft X-ray emission via the MLCT intermediate states can be interpreted as valence MLCT excitations within a one-electron picture. On the other hand, resonant soft X-ray emission via the intra-atomic Ni 2p–3d intermediate state corresponding to the white line excitation shows significant electron correlation effects.

A study of the electronic structure of ultrathin AlAs layers buried in GaAs(100) and their interfaces is presented. Al L-2,L-3 soft-X-ray-emission (SXE) spectra from the AlAs layers were measured. ...

Ultrathin AlAs(100) layers of 1-, 2-, and 5-ML thickness buried in GaAs are investigated by nb initio calculations. Unique experimental soft-x-ray emission spectra are explained in terms of interfa ...

The electronic structure of the conjugated polymer, polyaniline, has been studied by resonant and nonresonant X-ray emission spectroscopy using synchrotron radiation for the excitation. The measurements were made on polyaniline and a few doped (protonated) phases for both the carbon and nitrogen contents. The resonant X-ray emission spectra show depletion of the {\pi} electron bands due to the selective excitation which enhances the effect of symmetry selection rules. The valence band structures in the X-ray emission spectra attributed to the {\pi} bands show unambiguous changes of the electronic structure upon protonation. By comparing to X-ray absorption measurements, the chemical bonding and electronic configuration is characterized., Comment: 8 pages, 8 pictures, http://jcp.aip.org/resource/1/jcpsa6/v111/i10/p4756_s1