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We have investigated polarization rotation associated with phonon dynamics in the relaxor ferroelectrics Pb[(Mg1/3Nb2/3)1–xTix]O3. The intensity distributions of the diffuse scattering patterns show intensity- crossover behavior in the monoclinic-C(MC) phase over a wide Ti composition range (29 < x < 32 mol%). The transverse acoustic (TA) mode of the crossover region along the [001] direction softens and is damped, strongly correlating with the central peak intensity, which originates in the polar regions. These results indicate that the lattice can easily deform in the MC phase, and the polarization can rotate easily by associating with the TA mode.

Mesoscopic polarization structures such as polar nanoregions and polarization domain walls are the key factors connecting microscopic fundamental polarization structures with macroscopic practical dielectric properties. A snapshot observation of the domain in the relaxor ferroelectrics $\mathrm{Pb}[{(\mathrm{M}{\mathrm{g}}_{1/3}\mathrm{N}{\mathrm{b}}_{2/3})}_{1\text{\ensuremath{-}}x}\mathrm{T}{\mathrm{i}}_{x}]{\mathrm{O}}_{3}$ just in the vicinity of morphotropic phase boundary region was performed by use of 7-ps single shot soft x-ray laser pulse. A self-assembled evolution of the oblique polarization domain was observed in $\mathrm{Pb}[{(\mathrm{M}{\mathrm{g}}_{1/3}\mathrm{N}{\mathrm{b}}_{2/3})}_{72.2}\mathrm{T}{\mathrm{i}}_{27.8}]{\mathrm{O}}_{3}$ under the sample temperature decreased with the thermal equilibrium condition. Based on energetic discussion, antiphase shift of domain wall pairs keeping flat boundaries was proposed for the dielectric response. A sharp enhancement in the dielectric response at the vicinity of morphotropic phase boundary region reported previously was recognized as evidence for the hierarchic nature of the present oblique polarization domain wall.

The CXD method have been shown to be applicable to the crystal characterization as well as the domain observation. The present CXD technique could evaluate the crystal coherence length up to 10 μm ...

A prototype split-and-delay unit (SDU) for X-ray free-electron laser (XFEL) pulses is proposed based on the Graeff–Bonse four-Bragg-reflection interferometer by installing 12.5° slopes. The SDU can continuously provide a delay time from approximately −20 to 40 ps with a resolution of less than 26 fs. Because the SDU was constructed from a monolithic silicon crystal, alignment is straightforward. The obtained thoroughputs of the SDU reached 0.7% at 7.46 keV and 0.02% at 14.92 keV. The tunability of the delay time using the proposed SDU was demonstrated by finding the interference effects of the split X-rays, and the time resolution of the proposed SDU was evaluated using the width of the interference pattern recorded on the X-ray charge-coupled device camera by changing the energy,i.e.longitudinal coherence length, of the incident X-rays. It is expected that the proposed SDU will be applicable to XFEL experiments using delay times from tens of femtoseconds to tens of picoseconds,e.g.intensity correlation measurements.

The phase diagram and the relationship between the crystal coherence length and electrical response of ${\mathrm{Pb}[({\mathrm{Mg}}_{1/3}{\mathrm{Nb}}_{2/3})}_{1\ensuremath{-}x}{\mathrm{Ti}}_{x}]{\mathrm{O}}_{3}$ (PMN-$x\mathrm{PT}$) near the morphotropic phase boundary (MPB) have been precisely investigated using a single crystal with a Ti composition gradient by synchrotron x-ray diffraction and inelastic light scattering at room temperature. The crystal has two boundaries at Ti compositions of 29.0 and 34.7 mol% which correspond to the phase boundaries between the monoclinic $B ({M}_{B})$ and $C ({M}_{C})$ phases and between the ${M}_{C}$ and tetragonal $(T)$ phases, respectively. The crystal coherence length determined from the widths of Bragg peaks varies by over two orders of magnitude in a 10 mol% range of the Ti composition. It is shown that there is a strong negative correlation between the electrical response and the crystal coherence length at the sub-$\ensuremath{\mu}\mathrm{m}$ scale. The results are explained by the size effects of domains near the MPB.

An experimental system for X-ray magnetic diffraction (XMD) under extreme conditions was constructed on the beamline BL39XU at SPring-8. This system aims at studying magnetic properties of ferromagnets through the measurements of magnetic form factors under the conditions of low temperature (5 K), high magnetic field (6 T) and high pressure (10 GPa). This system consists of a superconducting magnet (SCM), a diamond anvil cell (DAC), a two-axis manipulator for the DAC, a five-axis goniometer for the SCM, and an X-ray polarizer with a phase plate. Details of this system are presented. Experimental results on uranium telluride are shown as a performance test with this instrumentation.

X-ray magnetic diffraction (XMD) experiments of ferromagnetic YTiO 3 were performed. The orbital-magnetic form factor (L) and the spin-magnetic form factor (S) were individually measured by utilizing the LS separation method of the XMD. The experiments consisted of two parts. The first was the measurement of the orbital-magnetic form factor to examine whether the orbital moment of this compound was quenched or not. The second was the measurement of the spin-magnetic form factor to examine whether the ordered orbital of Ti-3d electrons was observed by the XMD. The result of the first experiment suggested quenching of the orbital moment. In the second experiment, the spin-magnetic form factor was observed for the total 22 reciprocal-lattice points. Calculated spin-magnetic form factor with a model wave function of the ordered orbital reproduced the observed one well. This result shows that the ordered orbital of Ti-3d electrons can be observed by the XMD.

We have performed the two-photon correlation measurement of synchrotron radiation in the VUV region to characterize the photon statistics of the light. The explicit bunching effect of the second-order coherence is observed, which implies that synchrotron radiation has a chaotic nature. We also estimate the electron beam emittance of a stored beam. The two-photon correlation measurement will be utilized to diagnose the storage ring and to characterize the coherence properties of X-ray free electron laser in the future.

The development of highly reflective multilayer mirrors for use in the wavelength region around 6 nm is desired for X-ray photoemission spectroscopy for inner-shell excitation using a Schwarzschild objective. For this application, reflectivity is the most critical parameter determining the performance of multilayer mirrors, because the reflectivity of multilayers in the 6 nm region is generally very low. We have designed CoCr/C multilayer mirrors with a comparatively high reflectivity at around normal incidence and have fabricated them by magnetron sputtering. The measured peak reflectivity is about 16% at a wavelength of around 6 nm and an incident angle of 88°. The reflectivity remains almost constant for 4 h under 300°C in an Ar atmosphere.

This paper reviews recent progress in the source development of intense coherent x-rays and the applications in the research fields such as material science and laser processing in Japan Atomic Energy Agency (JAEA). In the source development, the polarization of the fully spatial coherent 13.9 nm soft x-ray laser (SXRL) in the transient collisional excitation (TCE) scheme was investigated experimentally. The result indicated that the SXRL beam was strongly polarized in the direction perpendicular to the target surface. In the alternative schemes toward the short wavelength region, intense higher-order harmonics with the photon energy of more than 300 eV was observed from a relativistic plasma generated with the laser intensity higher than 1018 W/cm2. In the applications of the 13.9 nm TCE laser, we observed temporal evolution of surface distortion of Pt sample pumped by a 80 fs optical pulse by use of x-ray laser interferometer using double Lloyd’s mirrors and reflectometer. In the study of SXRL ablation, the melting depth of the substances using single shot SXRL exposure was measured, and the result was quantitatively consistent with the calculated result based upon the spallative ablation model by molecular-dynamics code.

At the Institute of Laser Engineering, Osaka University, we have obtained Ni-like x-ray lasers of various atomic number elements, including many shorter wavelength Ni-like lasing lines around 5nm. The saturated amplification of Ni-like Ag lasing line at the wavelength of 13.9nm have been observed. Using these x-ray lasers, we are preparing the application experiments such as probing a laser-produced plasma with an x-ray laser interferometer.

Studies of magnetic materials by spectroscopy and diffractometry are developed further using high brilliant light sources at SPring-8. Polarization tunability of incident photons and polarization analysis of scattered X-rays are a promising item for studying electronic and magnetic structures in various magnetic materials. Feasibility of the diffractometer, installed on BL39XU for X-ray magnetic scattering and absorption experiments, is shown by recent results of X-ray magnetic circular dichroism, X-ray magnetic diffraction, and X-ray resonant magnetic scattering. For the experiments, phase retarder using a diamond single crystal plays an essential role for regulation of the polarization states and for recording the magnetic effects with high accuracy.

Polarization tunability and analysis of X-rays is one of the most advancing features of third-generation synchrotron radiation sources. In order to apply such developments to the observation of magnetic effects, a diffractometer for X-ray magnetic absorption and scattering experiments was constructed on BL39XU at SPring-8. The efficiency of the apparatus is clearly demonstrated by several observations of the magnetic effects. In particular, a diamond phase plate plays an essential role in regulating both circular and linear polarization states.

Preparations are underway for the experimental investigation of the roughness of magnetic interfaces in rare-earth multilayers by combining the grazing-angle X-ray scattering technique with the resonant magnetic scattering of hard X-rays. Theoretical considerations show that for small scattering angles, 2theta, the asymmetry ratio, A = [I(+) - I(-)]/[I(+) + I(-)], depends on 2theta and varies as 1/cos theta. The first step towards the goal of determining the magnetic roughness has been taken by measuring the chemical roughness (via specular reflectivity) of a Gd thin-film sample at five photon energies close to the L(3) absorption edge, which yielded the dispersion corrections, f' and f'', to the Gd atomic form factor in good agreement with the calculation of CromerLiberman [J. Chem. Phys. (1970), 53, 1891-1898].

A few kinds of x‐ray optics together with x‐ray sciences developed at the Photon Factory ring and the Tristan accumulation ring are described. As an extension a description is also given about a feasibility study under preparation for using the 5 nm rad synchrotron radiation from a 120 pole undulator at the Tristan main ring. This activity, if achieved, will function as a bridge between a third‐ and a fourth‐generation light source because a few of these experiments in planning are considerably related to the coherent nature of fourth‐generation light in the x‐ray domain, so that a perspective view on that will be available.

Complementary use of coherent x-ray diffraction (CXD), x-ray diffuse scattering, conventional x-ray diffraction techniques, and dielectric measurements has enabled us to investigate Pb(Zn${}_{1/3}$Nb${}_{2/3}$)-9%PbTiO${}_{3}$ with a multiple-length-scale approach from the macroscale (lattice constants, bulk averaged) and microscale to the nanoscale [polar nanoregions (PNRs)] and discuss the contribution of each scale to the dielectric permittivity. We estimate that diffuse scattering mainly originates from intra-PNR dynamics, which contributes to ``ionic'' polarization and results in high-frequency permittivity. Meanwhile, the appearance of intermediate submicrometer (sub-$\ensuremath{\mu}$m) structures observed by CXD is consistent with the appearance of low-frequency dielectric relaxation. The sub-$\ensuremath{\mu}$m structures exhibit large fluctuations at ${T}_{\mathrm{c}}$. This is also consistent with previously reported results obtained by x-ray intensity fluctuation spectroscopy and should give a lower limit for the low-frequency dielectric dispersion. We have suggested that the fluctuation is due to the competition between the growth of sub-$\ensuremath{\mu}$m structures and the appearance of the macroscopic tetragonal-ferroelectric phase. Since the present CXD mainly detected the strain field spreading throughout the crystal, we here demonstrate that the sub-$\ensuremath{\mu}$m structures are due to networks among PNRs connected by the strain field.

This paper gives an overview of recent progress in the study of laser-driven plasma x-ray lasers in Japan Atomic Energy Agency (JAEA). Fully spatial coherent plasma soft x-ray laser (SXRL) at 13.9 nm with 0.1 Hz repetition rate is now routinely used in the wide variety of the applications: The highlights of these applications are the study of fluctuation in the atomic structure of ferroelectric substances under the phase transition using double SXRL probe technique and the first observation of surface dynamics of laser ablation with 10 ps-time and 1 nm-depth resolution using a single-shot SXRL interferometer.

We made a new polarization analyzing system for measuring a rotation of major axis of elliptical polarization in x‐ray magnetic resonant scattering. This system, based on a two‐axis diffractometer, is characterized by introducing a 45° linearly polarized x‐ray incident beam. Design and performance of the system are described. The rotation can be measured with precision of 0.2°–0.3° at the vicinity of Gd L3‐absorption edge where the maximum rotation is about −2°.

We developed a new soft X-ray speckle intensity correlation spectroscopy system by use of a single shot high brilliant plasma soft X-ray laser. The plasma soft X-ray laser is characterized by several picoseconds in pulse width, more than 90\% special coherence, and 10$^{11}$ soft X-ray photons within a single pulse. We developed a Michelson type delay pulse generator using a soft X-ray beam splitter to measure the intensity correlation of X-ray speckles from materials and succeeded in generating double coherent X-ray pulses with picosecond delay times. Moreover, we employed a high-speed soft X-ray streak camera for the picosecond time-resolved measurement of X-ray speckles. We performed the X-ray speckle intensity correlation measurements for probing the relaxation phenomena of polarizations in polarization clusters in the paraelectric phase of the ferroelectric material BaTiO$_{3}$ near its Curie temperature and verified its performance., シングルショット高輝度プラズマX線レーザーを用いた全く新しい軟X線スペックル強度相関分光システムを開発した。プラズマX線レーザーは、数ピコ秒パルス幅,90\%以上の空間コヒーレンス、そして1パルス辺り10$^{11}$個のフォトン数を持つ優れた光源である。われわれは軟X線ビームスプリッターを用いたマイケルソン型遅延パルス生成器を開発し、ピコ秒の遅延時間を持つコヒーレントダブル軟X線パルスの生成に成功した。さらに物質からのスペックル信号をピコ秒時間スケールで計測するために高速軟X線ストリークカメラを用いた。開発した分光システムの性能を検証するため、誘電体物質であるチタン酸バリウムのキュリー温度近傍で生じる分極クラスターの緩和現象観測に本システムを用い、有効性を確認した。

X-ray resonance exchange scattering has been measured at the Nd L 2,3 absorption edges on the (440) Bragg reflection in a ferromagnetic Nd 2 Fe 14 B single crystal. The magnetic spectrum at the L 2 -edge reflects the spin polarization of unoccupied 5 d -bands of Nd due to electric dipole transitions. The magnetic spectrum at the L 3 -edge shows a more complicated structure than that at the L 2 -edge. The difference in magnetic spectra between the L 2 - and L 3 -edges is discussed from the viewpoints of L S coupling in 5 d -bands and the contributions of electric quadrupole transitions to the highly localized and partially vacant 4 f -states.

This paper gives an overview of recent progress of laser-driven plasma x-ray lasers in Japan Atomic Energy Agency (JAEA). Fully spatial coherent plasma x-ray laser (XRL) at 13.9 nm with 0.1 Hz repetition rate has been developed using new driver laser system TOPAZ, and the succeeding optimization of the pumping condition has realized more efficient generation of the coherent x-ray pulse. The 0.1 Hz XRL is now routinely used in the wide variety of the application experiments: The highlights of these applications are the study of fluctuation in the atomic structure of ferroelectric substances under the phase transition using the double XRL probe beam technique and the construction of new x-ray laser interferometer to observe nano-scale dynamics of materials.

Magnetic effects in the X-ray absorption process have been measured using circularly polarized X-rays emitted from an elliptical multipole wiggler. Magnetic XANES spectra on the K -edge of Fe and Ni taken by the transmission method show positive and negative spin polarizations, respectively, near the Fermi level which are consistent with the results in literature. A large positive magnetic XANES spectrum on the Nd L 2 -edge of Nd 2 Fe 14 B compound measured by the fluorescent method indicates that the unoccupied 5 d -bands are polarized due to a significant hybridization between 4 f - and 5 d -states. The magnetic XANES spectrum on the Nd L 3 -edge has a structure below the Fermi level, suggesting a quadrupole transition contribution of the partially vacant majority band of 4 f -states.

Time-dependent speckle pattern of paraelectric barium titanate observed in a soft x-ray laser pump-probe measurement is theoretically investigated as a correlated optical response to the pump and probe pulses. The scattering probability is calculated based on a model with coupled soft x-ray photon and ferroelectric phonon mode. It is found that the speckle variation is related with the relaxation dynamics of ferroelectric clusters created by the pump pulse. Additionally, critical slowing down of cluster relaxation arises on decreasing temperature towards the paraelectric-ferroelectric transition temperature. Relation between critical slowing down, local dipole fluctuation and crystal structure are revealed by quantum Monte Carlo simulation., 9 pages, 8 figures

We have developed a new method to investigate the relaxation time of the dipole moment in polarization clusters in BaTiO3. Time correlation of speckle intensities was measured by the use of a double pulsed soft x-ray laser. The evolution of the relaxation time of the dipole moment near the Curie temperature (T(C)) was investigated. The maximum relaxation time (approximately 90 ps) is shown to appear at a temperature of 4.5 K above the T(C), being coincident with the one where the maximum polarization takes place. This method is widely applicable to any other critical decay processes at phase transitions.

We carry out a theoretical investigation to clarify the dynamic property of photo-created nano-sized ferroelectric cluster observed in the paraelectric BaTiO3 as a real time correlation of speckle pattern between two soft X-ray laser pulses, at just above the paraelectric-ferroelectric phase transition temperature. Based on a model with coupled soft X-ray photon and ferroelectric phonon mode, we study the time dependence of scattering probability by using a perturbative expansion approach. The cluster-associated phonon softening as well as central peak effects are well reproduced in the phonon spectral function via quantum Monte Carlo simulation. Besides, it is found that the time dependence of speckle correlation is determined by the relaxation dynamics of ferroelectric clusters. Near the transition point, cluster excitation is stable, leading to a long relaxation time. While, at high temperature, cluster structure is subject to the thermal fluctuation, ending up with a short relaxation time., 9 pages, 3 figures

X‐ray diffraction has been conducted to study the microscopic‐scale structures for 0.72Pb(Mg1/3Nb2/3)O3‐0.28PbTiO3 relaxor ferroelectrics in a high external DC field during phase transition. Clear quasi‐periodic structures were observed along 〈111〉 and 〈1‐11〉 directions near Tc induced by the high external DC field. The formation of these periodic structures are interpreted as a type of Coulomb interaction among adjacent polar clusters. The cluster size was estimated to be 17nm. It was also found that the dominating interaction direction among clusters (periodic direction) were changeable among 〈111〉 and 〈1‐11〉 as temperature changed.

A graded and broadband Mo/Si multilayer mirror for EUV spectroscopy is demonstrated. This mirror has an average reflectivity profile of 16% in the wavelength region from 15 nm to 17 nm and an effective area of 1100-1500 mm(2). This reflectivity is about 4 times larger than that of a standard Mo/Si multilayer mirror on a 1 in. diameter substrate, showing that the mirror can be used for measuring EUV fluorescence at wavelengths in the region around 15 nm to 17 nm.

Dual relaxation processes have been observed in a straightforward way by photon correlation spectroscopy (PCS) for polarization clusters in barium titanate during paraelectric-ferroelecric phase transition. The observed fast relaxation process for polarization clusters covers a broad temperature region and exhibits an anomaly near the Curie temperature (T-C). The slow relaxation process occurs at 4 K above T-C and covers a limited temperature region, where the relaxation time exhibits an approximately linearly decreasing behavior. This study provides deep insight into the complex phase transition of barium titanate. (c) 2015 The Japan Society of Applied Physics

Recent progress in x-ray laser (XRL) research in Japan Atomic Energy Agency (JAEA) is reviewed. The repetition-rate of the x-ray laser has been improved from each0 minutes to0 seconds (0.1 Hz) by installing new driver laser, TOPAZ, which allows us to promote the applications of fully spatial coherent3.9 nm laser in the wide variety of research fields such as material science, single-shot x-ray holography and atomic physics. In order to improve the present performance of the x-ray lasers, we have investigated the possibilities of the enhancement of the peak brilliance using v-groove target and the generation of circularly polarized x-ray laser under a strong magnetic field. Towards shorter wavelength x-ray lasers, we have investigated several schemes. One is the use of reflection of the light by relativistic plasma mirror driven by laser-wake-field, and the other is photo-pumping scheme using Kα emission from a solid target.

The polarization clusters existing in both the ferroelectric and the paraelectric phase of $\mathrm{B}\mathrm{a}\mathrm{T}\mathrm{i}{\mathrm{O}}_{\mathrm{3}}$ are directly observed and characterized for the first time by a picosecond soft x-ray laser speckle technique. These dynamic clusters appear continuously across the Curie temperature ${T}_{c}$. The clusters' distance increases approximately linearly with temperature, while their mean size does not change significantly. The polarization exhibits a maximum at a temperature about 5 \ifmmode^\circ\else\textdegree\fi{}C above ${T}_{c}$. The clusters' short-range correlation strength diverges as $(T\ensuremath{-}{T}_{c}{)}^{\ensuremath{-}0.41\ifmmode\pm\else\textpm\fi{}0.02}$ as temperature decreases toward ${T}_{c}$.

A picosecond x-ray laser speckle has been conducted to study the dynamics of a disordered surface domain structure (${\mathrm{B}\mathrm{a}\mathrm{T}\mathrm{i}\mathrm{O}}_{3}$ with $90\ifmmode^\circ\else\textdegree\fi{}$ $c/a$ domains) as a function of temperature for the first time. The transient surface structures induced by ferroelectric domains decrease as temperature increases towards the Curie temperature ${T}_{c}$ and completely disappear above ${T}_{c}$. The dramatic change of the spatial configuration of the $c/a$ domains was observed to occur from a temperature $2\text{ }\ifmmode^\circ\else\textdegree\fi{}\mathrm{C}$ below ${T}_{c}$, near which the average correlated domain size at equilibrium decreases as $({T}_{c}\ensuremath{-}T{)}^{0.37\ifmmode\pm\else\textpm\fi{}0.02}$.

By traveling wave irradiation with a compact, 2‐beam, 1‐ps, 20‐J CPA Nd‐glass laser dedicated to x‐ray laser research, saturated amplification has been demonstrated in Ni‐like Ag at 13.9 nm and Ni‐like Sn at 12.0 nm. High gain amplification has been also obtained in Ni‐like La at 8.8 nm and with gaseous targets in Ne‐like Ar at 46.9 nm and Ni‐like Xe at 9.98 nm. Generation of highly coherent x‐ray laser is planned by injection seeding of the plasma amplifier. The newly developed 340‐TW Ti‐sapphire laser may enable generating exceedingly high power x‐ray radiation which will be useful for pumping inner‐shell ionization x‐ray lasers.

We have performed an x-ray photon correlation spectroscopy measurement of 91%Pb(Zn1/3Nb2/3)O3-9%PbTiO3 and found a slow structural fluctuation in time near TC. The slow fluctuation consists of long-term and short-term fluctuations. We have derived the short-term fluctuation from the intensity fluctuations and found out the relaxation time to be an order of 10 s. It is suggested that the slow fluctuation is owing to the competition between macroscopic tetragonal symmetry and the microscopic orthorhombic symmetry. The competition should be a main reason for the low-frequency dielectric permittivity.

The use of a combination of coherent X-rays from a third-generation synchrotron light source and ultraprecise Kirkpatrick-Baez mirrors enables us to apply nanofocused hard X-rays in solid-state physics. We developed an apparatus for X-ray intensity fluctuation spectroscopy using the nanofocused hard X-rays and applied it to the study of relaxor ferroelectrics. We have successfully detected a large and slow intensity fluctuation of scattered X-rays above cubic-to-tetragonal phase transition temperature with a characteristic time scale on the order of 10 s. We speculated that the intensity fluctuation originates from domain number fluctuation, which is directly related to the dielectric response, particularly the frequency dispersion.

The average, spontaneous (zero field) structure of the polar nanoregions (PNRs) in a single crystal specimen of the relaxor ferroelectric 0.72Pb(Mg1∕3Nb2∕3)O3–0.28PbTiO3 has been characterized above Tm by partially coherent x-ray diffraction. At these temperatures, the PNRs are randomly distributed within the crystal and exhibit dimensions of 17 and 10nm along the [001] and [100] directions, respectively. Based on the results of a previous study [Z. Guo et al., J. Appl. Phys. 101, 053505 (2007)], the long dimension of the PNR is observed to reorient preferentially along the four degenerate diagonal axes [1±1±1], which is believed to contribute to the high electromechanical response in these relaxor materials.

X-ray diffraction experiment has been conducted to study the microscopic-scale structures for 0.72PMN-0.28PT relaxor ferroelectrics in a high external dc field during phase transition. Clear quasiperiodic structures were observed along ⟨111⟩ and ⟨1–11⟩ directions near TC. These structures are interpreted as originating from strong Coulomb interactions among adjacent polar clusters. The projected cluster size (correlation length) was estimated to be 17nm. It was also found that the dominating cluster’s orientation and their interaction direction (periodic direction) were changeable among ⟨111⟩ and ⟨1–11⟩ as temperature changed.

The X-ray resonance exchange scattering (XRES) has been measured at the Nd L 2,3-edges on the 330, 440 and 550 Bragg reflections in a ferromagnetic Nd2Fe14B single crystal. The XRES results at the L 2-edge reflect the spin polarization of unoccupied 5d-bands of Nd due to electric dipole transitions. Those at the L 3-edge show the possibility of electric quadrupole transitions to the highly localized 4f-states. The temperature dependence of XRES confirms the sensitivity to the local magnetic moment of specific site. The magnetic moments of Nd 4f and 4g sites rotate from the c-axis with different angles below spin reorientation temperature.

The first observation of the rotation of the major axis on the scattered X-ray at magnetic resonance has been performed. This rotatory power named “X-ray Magnetic Kerr Effect” is applicable to the investigation of spin polarization of unoccupied states. The rotation has been measured with 1eV increment between 6eV below the Gd L3 absorption edge and 6eV above the Gd L3 absorption edge. The maximum rotation is about minus 2 degrees observed at about 4eV below the edge. The peak width is about 2eV. This spectrum correspond to the 4f-state. The magnitude of the rotation between 3eV below the edge and 5eV above the edge is about 1 degree. The sign of the rotation change from plus to minus at the vicinity of the edge. This spectrum correspond to the 5d-band structure. These features agree fairly well with the theoretical prediction.

An instrument for polarization analysis in magnetic x‐ray scattering is now being commissioned. Its side view is shown in Fig. 1, and inserts in the figure show the polarization state of x rays at various spots. This system adopts no flipping of the magnetic field over a hard magnetic material which needs large saturation magnetization. Its basic components are (a) a polarizer monochromator which converts the horizontal polarization into 45° one, (b) a two‐axis diffractometer having a magnet for a sample, and (c) a polarization analyzer crystal. Furthermore, the magnet accommodates a cryostat for cooling a sample and a solid state detector covered with a magnetic shield cap for measuring fluorescent x rays. The electric vector of linearly polarized x rays is rotated through scattering from a magnetic sample because both magnetic scattering amplitudes, σ0 to σf and π0 to πf, are different from those of the electric one. It will be therefore possible to investigate the spin‐resolved unoccupied density of st...

Temperature dependence of the exchange diffraction spot intensity from the cleaved face (001) of nickel oxide is measured for the cases of very small and comparatively large penetration depth of electron beam concerning the surface barrier resonance in LEED. The exchange reflexion intensity is corrected for the Debye-Waller factors in order to reveal the temperature dependence of the sublattice magnetization. The effective critical exponent of the sublattice magnetization is determined to be 0.89±0.01 as the proper value for the top-most surface layer. The thickness of the surface layers, which is characterized by the same value of the critical exponent as the top-most surface layer, becomes thicker than the mean absorption distance when the temperature is raised up to 0.9 in T / T N .

A resonance-type X-ray magnetic scattering at the K -absorption edge was first observed in 220 Bragg reflection of ferromagnetic Ni single crystal. Further a theoretical discussion on the resonance magnetic scattering curve observed was carried out; A difference of the oscillator-strength density for each direction of the spins was also derived from this curve. The oscillator-strength density for minority spin excesses that for the majority spin between the Fermi level and 25 eV above the level. The difference of oscillator-strength density amounts to about 1×10 -4 /Ry at the maximum.

Characteristics of X-ray magnetic Bragg scattering are discussed. Synchrotron X-ray radiation is proved to be a suitable source for examining X-ray magnetic scattering by means of polarization analysis or resonance scattering. Some eminance in X-ray magnetic Bragg scattering is pointed out.