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Diamond has two crystallographically inequivalent sites in the unit cell. In doped diamond, dopant occupation in the two sites is expected to be equal. Nevertheless, preferential dopant occupation during growth under nonequilibrium conditions is of fundamental importance, for example, to enhance the properties of nitrogen-vacancy (N-V) centers; therefore, this is a promising candidate for a qubit. However, the lack of suitable experimental techniques has made it difficult to study the crystal- and chemical-site-resolved local structures of dopants. Here, we confirm the identity of two chemical sites with asymmetric dopant incorporation in the diamond structure, via the photoelectron holography (PEH) of heavily phosphorus (P)-doped diamond prepared by chemical vapor deposition. One is substitutionally incorporated P with preferential site occupations and the other can be attributed to a PV split vacancy complex with preferential orientation. The present study shows that PEH is a valuable technique to study the local structures around dopants with a resolution of crystallographically inequivalent but energetically equivalent sites/orientations. Such information provides strategies to improve the properties of dopant related-complexes in which alignment is crucial for sensing of magnetic field or quantum spin register using N-V centers in diamond.

An endstation dedicated to angle-resolved photoemission spectroscopy (ARPES) using a soft X-ray microbeam has been developed at the beamline BL25SU of SPring-8. To obtain a high photoemission intensity, this endstation is optimized for measurements under the condition of grazing beam incidence to a sample surface, where the glancing angle is 5° or smaller. A Wolter mirror is used for focusing the soft X-rays. Even at the glancing angle of 5°, the smallest beam spot still having a sufficient photon flux for ARPES is almost round on the sample surface and the FWHM diameter is ∼5 µm. There is no need to change the sample orientation for performing k x − k y mapping by virtue of the electron lens with a deflector of the photoelectron analyzer, which makes it possible to keep the irradiation area unchanged. A partially cleaved surface area as small as ∼20 µm was made on an Si(111) wafer and ARPES measurements were performed. The results are presented.

The KamLAND-Zen 800 experiment is searching for the neutrinoless double-beta decay of $^{136}$Xe by using $^{136}$Xe-loaded liquid scintillator. The liquid scintillator is enclosed inside a balloon made of thin, transparent, low-radioactivity film that we call Inner Balloon (IB). The IB, apart from guaranteeing the liquid containment, also allows to minimize the background from cosmogenic muon-spallation products and $^{8}$B solar neutrinos. Indeed these events could contribute to the total counts in the region of interest around the Q-value of the double-beta decay of $^{136}$Xe. In this paper, we present an overview of the IB and describe the various steps of its commissioning minimizing the radioactive contaminations, from the material selection, to the fabrication of the balloon and its installation inside the KamLAND detector. Finally, we show the impact of the IB on the KamLAND background as measured by the KamLAND detector itself., 23 pages, 16 figures, to be submitted to JINST

The bulk photovoltaic effect (BPVE) is a mechanism of recent focus for novel solar cells that exceed the power conversion efficiency of p–n junction solar cells because of the quantum mechanical effect to generate photocurrent known as shift current. Ferroelectrics are receiving attention again because of their high voltage generation by the BPVE and converse piezoelectric effect to realize high performance optical actuators. We have investigated the BPVE in ferroelectric BiFeO3 (BFO) single crystal thin films, whereby the photovoltage was enhanced by Mn doping, and 852 V generation was demonstrated at 80 K. The enhancement mechanism was also investigated using soft and hard X-ray photoelectron spectroscopy (SXPES, HAXPES), and soft X-ray absorption spectroscopy with synchrotron radiation. This report reveals a way to new voltage source applications employing the BPVE for high impedance devices with ferroelectrics. Important aspects for designing ferroelectric materials by impurity doping are also discussed.

We report magnetic domain formation control within micro-scale polycrystalline Ni wires on a single-crystal Y-cut 128° LiNbO3 substrate. X-ray magnetic circular dichroism photoemission electron microscopy (XCDM-PEEM), micromagnetic simulations, and magnetoresistance (MR) measurements allowed us to estimate the uniaxial magnetic anisotropy induced by the magnetoelastic effect that originated at the interface between each Ni layer and the LiNbO3 substrate. Comparison of the XMCD-PEEM and MR measurement results shows that the competition between the shape magnetic anisotropy and the uniaxial magnetic anisotropy parallel to the orientation flat (OF) direction of the substrate leads to variations in both the magnetization order and the magnetization reversal process. The uniaxial magnetic anisotropy is estimated to be approximately 3.3 kJ/m3. This heterojunction structure composed of ferromagnetic and ferroelectric layers thus offers alternative ways to produce artificial functional multiferroic materials and devices.

The atomic scale characterization of dopant atoms in semiconductor devices to establish correlations with the electrical activation of these atoms is essential to the advancement of contemporary semiconductor process technology. Spectro-photoelectron holography combined with first-principles simulations can determine the local three-dimensional atomic structures of dopant elements, which in turn affect their electronic states. In the work reported herein, this technique was used to examine arsenic (As) atoms doped into a silicon (Si) crystal. As 3d core level photoelectron spectroscopy demonstrated the presence of three types of As atoms at a total concentration of approximately 1020 cm–3, denoted as BEH, BEM, and BEL. On the basis of Hall effect measurements, the BEH atoms corresponded to electrically active As occupying substitutional sites and exhibiting larger thermal fluctuations than the Si atoms, while the BEM atoms corresponded to electrically inactive As embedded in the AsnV (n = 2–4) type cluste...

Two types of optical choppers for time-resolved measurements in soft X-ray beamlines of synchrotron radiation facilities were developed, which are utilized under ultra-high-vacuum conditions., Two types of optical choppers for time-resolved measurements at synchrotron radiation soft X-ray beamlines have been developed. One type uses an air-spindle-type rotation mechanism with a two-stage differential pumping system to maintain the ultra-high vacuum of the X-ray beamline, and the other uses a magnetic bearing. Both can be installed at the soft X-ray beamlines at SPring-8, greatly improving the accessibility of pump-and-probe spectroscopy. The combination of X-ray chopper and pump-and-probe photoemission electron microscope at SPring-8 provides drastic improvements in signal-to-noise ratio and resolution compared with techniques using high-voltage gating of channel plate detectors. The choppers have the capability to be used not only at synchrotron radiation facilities but also at other types of soft X-ray and VUV beamlines.

We present a precision analysis of the ^{136}Xe two-neutrino ββ electron spectrum above 0.8 MeV, based on high-statistics data obtained with the KamLAND-Zen experiment. An improved formalism for the two-neutrino ββ rate allows us to measure the ratio of the leading and subleading 2νββ nuclear matrix elements (NMEs), ξ_{31}^{2ν}=-0.26_{-0.25}^{+0.31}. Theoretical predictions from the nuclear shell model and the majority of the quasiparticle random-phase approximation (QRPA) calculations are consistent with the experimental limit. However, part of the ξ_{31}^{2ν} range allowed by the QRPA is excluded by the present measurement at the 90% confidence level. Our analysis reveals that predicted ξ_{31}^{2ν} values are sensitive to the quenching of NMEs and the competing contributions from low- and high-energy states in the intermediate nucleus. Because these aspects are also at play in neutrinoless ββ decay, ξ_{31}^{2ν} provides new insights toward reliable neutrinoless ββ NMEs.

“Japan Synchrotron Radiation Research Institute” was presented by Toyohiko Kinoshita (Japan Synchrotron Radiation Research Institute) on April 17, 2018 at the ORCID Japan Member Meeting in Tokyo.

PEEM is one of the imaging type photoelectron microscopy (Kinoshita et al. in J Phys Soc Jpn 82 2013 [1]). The apparatus is equipped with some electrostatic lens systems, a microchannel plate (MCP) and a fluorescent screen. When excitation photons are injected onto a sample, photoelectrons including secondary electrons are emitted. The lens systems magnify and focus the images of spatial distributions of these electrons from the sample onto the MCP. Then the screen is illuminated by these amplified electrons. By using a charge coupled device (CCD) camera, a magnified image of the emitted electron distributions from the sample surface can be obtained. When a mercury lamp or a deuterium lamp is used as an excitation source, the distribution of the local work function of the surface becomes visible, since the photon energy is about 4 eV.

Grain-oriented Fe-3%Si steels are industrially important soft magnetic materials that are usually used in transformer cores but have also recently started to be used in motor cores [1]. Further improvements in the magnetic properties of grain-oriented steels are required to increase the efficiency of electrical machinery. The magnetic properties of grain-oriented steels strongly depend on the magnetic domain structures. The magnetic domains in grain-oriented steels mainly consist of the 180° basic domains and supplementary domains, such as lancet domains. The lancet domains, which occur due to a tilt angle of the [001] easy axis out of the steel surface (β), affect not only iron losses but also magnetostrictive noise. Therefore, it is important to understand the behavior of the lancet domains in order to further improve the magnetic properties. Many studies of the lancet domains [2-4] have been performed, for example, under applied stresses and external magnetic fields at the room temperature (RT). However, the behavior of lancet domains in the region above RT has not yet been investigated even though the operating temperature of transformers and electric motors are generally above RT. In this paper, the changes in the lancet domains of grain-oriented steels over the range from RT to the Curie point were observed using photoemission electron microscopy combined with X-ray magnetic circular dichroism (XMCD-PEEM). Moreover, the domain theory enabled us to quantitatively explain the observed temperature dependence of the lancet domains.

The proverbial ``canary in a coal mine'' is truly a thing of the past; nowadays zinc oxide is a key material in solid-state gas sensors, yet the mechanism by which doping can improve its performance is not fully understood. The authors use two-dimensional photoelectron diffraction to study thin films of tungsten-doped ZnO, and find clear evidence for substitution of segregated W atoms into Zn sites in the subsurface layer, which drastically improves the sensing response. This insight into the surface's structure-function relationship suggests how best to prepare these films for this important application.

The 3-D structures of the 90° closure domains in demagnetized Fe3%Si(110) steels occurring by the compressive stress were quantitatively analyzed using domain theory. The dependence of the compressive stress and the thickness in the 90° closure domains were evaluated using the proposed closure domain model with the 90° domain width. It was revealed that the 90° closure domain width decreases with an increase in compressive stress and steeply increases with a decrease in compressive stress. Moreover, our calculations predict that the critical compressive stress for the occurrence of the closure domains increase with the decrease in specimen thickness. The results suggest that when the thickness becomes thinner, enhancement of local compressive stress may be needed to refine 180° basic domains along the rolling direction. The validity of the calculation was confirmed by comparison with the past data and our presented domain observations by photoemission electron microscopy combined with X-ray magnetic circular dichroism.

Our previous study remained a question why biogenic guanine crystals that cause magnetic orientation under magnetic fields scattered light so intensively. In addition, the magnetic orientation analyses indicated that the crystal plate has primal and second axes of easy magnetization by diamagnetism, by which two-stage orientation of the crystal is caused. This paper aims to reveal the molecule arrangement inside the guanine crystal, which is related to optical and magnetic anisotropy. A transient light scattering increase from the guanine crystals that occurs with increasing and decreasing magnetic fields between 0 and 0.5 T was measured. The results indicate that the biogenic guanine crystal plates have a specific direction to scatter the light incidence. In the next, molecular vibrations in a single-crystal plate were investigated by utilizing the synchrotron microscopic Fourier transform infrared (FTIR) spectroscopy, and the obtained spectrum compared with that in magnetically oriented guanine crystal. The FTIR and attenuated total reflectance measurements reproducibly observed the IR absorbance spectrum peak appearance and disappearance when the polarization direction was set parallel and perpendicular to the morphological length of a biogenic guanine crystal. It is speculated that spectrum peak appearance and disappearance were caused by vibration of C = O bonds and N-H bonds in guanine crystal for polarization direction. In conclusion, we revealed that the surface and inside of biogenic guanine crystal possessed the anisotropy for molecule orientation related to optical and magnetic property.

Chemical state analysis of adhesive interfaces is important to understand an adhesion mechanism between two different materials. Although photoelectron spectroscopy (PES) is an ideal tool for such an analysis, the adhesive interfaces must be exposed to the surface because PES is essentially a surface sensitive technique. However, an in situ observation is possible by hard X-ray PES (HAXPES) owing to its large probing depth. In the present study, HAXPES is applied to investigate the adhesive interface between rubber and brass without exposing the interface. It is demonstrated that copper sulfides formed at the buried rubber/brass interface are distinguished from S-containing species in the rubber overlayer. The chemical state of the buried interface is compared with that of the “exposed” interface prepared by so-called a filter-paper method.

The observation of one-dimensional N2 inside single-walled carbon nanotubes raises the questions, how are the N2 molecules formed and how do they manage to make their way to this peculiar place? We have used N15 and C13 isotope labeled acetonitrile during the synthesis of single-walled carbon nanotubes to investigate this process. The isotope shifts of phonons and vibrons are observed by Raman spectroscopy and X-ray absorption. We identify the catalytic decomposition of acetonitrile as the initial step in the reaction pathway to single-walled carbon nanotubes containing encapsulated N2.

The angular distributions of photoelectrons and Auger electrons from single crystal surfaces show characteristic diffraction patterns, which contain information on the local atomic structures surrounding the emitter atoms. Using computational reconstruction processes on the diffraction patterns enables us to determine the local atomic structures of, for example, dopants, catalytic active sites, and surface/interface structures. This method has become known as "photoelectron holography (PEH)". Several advanced photoelectron analyzers for PEH are now available at beamlines at SPring-8, the world's largest synchrotron radiation facility. Recently, the use of micron-sized photon beams, as well as pump-and-probe time-resolved techniques has become possible with relatively high energy resolution. Here, the experimental apparatus and some representative applications are introduced.

This study aims to investigate the creep motion of a magnetic domain wall (DW) induced by spin-Hall torque (SHT) in a Ta/Co–Ni/Pt hetero-structured thin wire using photoemission electron microscopy. The displacement of the DW was recorded every time after the duration of an electric current pulse. Results revealed that the existence of pinning centers and the inhomogeneity of the thermal diffusion property of the wire may result in an unstable DW motion. On the contrary, this data also suggested that the SHT induced from both the Ta and Pt layers can significantly improve the DW velocity, which was found to be three orders of magnitude larger than that previously reported for the MgO/Co–Ni/Pt system (Taniguchi et al., Appl. Phys. Exp. 7, 053005 (2014)).

We have studied the orientational order in films of vertically aligned single walled carbon nanotubes, by means of resonant Raman spectroscopy, resonant X-ray absorption, and direct imaging. These methods investigate the hierarchical morphology at different length scales. Here, we discuss the systematic comparison of orientational order as function of wavelength in films with different inherent morphologies and provide thus a basis to quantitatively evaluate and compare the different experimental approaches.

We investigated the ion irradiation induced ferromagnetic state of FeRh thin films with 10 MeV I ion beam by the measurements of a superconducting quantum interference device (SQUID) magnetometer as well as of soft X-ray Magnetic Circular Dichroism (XMCD). It was clearly shown in the magnetization loops by SQUID measurements that the ion irradiation induced the ferromagnetic state in the FeRh thin films even below room temperature. This was also confirmed by the Fe L2,3-edge XMCD measurements for the irradiated FeRh film samples. However, we found that the irradiation ion fluence dependence on the magnetization was totally different between two measurement techniques. We also revealed by XMCD sum rule analysis that the ferromagnetism in the ion irradiated FeRh thin films was mainly dominated by the spin moment.

The fusion of graphene with silicon may provide an effective solution to the problem of scale in electronic devices. This approach will allow the excellent electronic properties of graphene to be combined with known Si device technologies. We review the epitaxial growth of graphene on Si substrates (GOS) for fabricating transistors. GOS has been multifunctionalized by controlling the orientation of the Si substrate. The site-selective epitaxy of GOS has also been developed by controlling the base SiC thin films. These results demonstrate that GOS is suitable for integrated devices.

The unexpected presence of a linear arrangement of co-axially oriented N2 molecules inside aligned single-walled carbon nanotubes is revealed by high resolution near-edge X-ray absorption spectroscopy. The encapsulated N2 molecules exhibit free stretching vibrations with a long electronic lifetime of the X-ray-excited anti-bonding π∗ states. Molecular dynamics simulations confirm that narrow-diameter nanotubes (d

Substantial upgrades have been made to the beamline BL25SU at SPring-8 for soft X-ray imaging and spectroscopy of solid-state materials. The upgraded beamline consists of two branches: a micro-beam branch with high energy resolution, and a nano-beam branch with small angular divergence. The beamline has been available for use since October 2014, following a half year commissioning period. We present here the beamline performance parameters, including resolving power, photon flux, and focused beam size, which are consistent with designed specifications.

A magnetic field is a powerful and precise tuning key for states of matters. It induces various new states with unexpected magnetic, electronic, and crystallographic properties. On the other hand, X-rays are widely used as one of the most powerful means to investigate crystal structures, electronic states, and magnetic phases in varieties of materials. However, the combination of these two tools has been very rare due to technical difficulties.

Soft-x-ray-excited angle-resolved photoelectron spectroscopy studies on silicon dioxide films formed utilizing oxygen radicals (ORs) and oxygen molecules (OMs) with or without forming gas annealing (FGA) are reported. The SiO2/Si interface structure formed utilizing ORs were only slightly influenced by FGA. On the other hand, although the thickness of oxide film formed utilizing OMs is weakly influenced by FGA, the FGA-induced nearly 10% decrease in the amounts of Si1+, Si2+, and Si3+ formed utilizing OMs were found. Therefore, the interface structure formed utilizing OMs is influenced by FGA.

We report the status of a scattering near-field microspectroscopy apparatus developed at SPring-8 using an infrared synchrotron radiation (IR-SR) source. It consists of a scattering type scanning near-field optical microscope and a Fourier transform infrared spectrometer. The IR-SR is used as a highly brilliant and broad-band IR source. This apparatus has potential for application in near-field spectroscopy with high spatial resolution beyond the diffraction limit. In order to eliminate background scatterings from the probe shaft and/or sample surface, we used higher harmonic demodulation method. The near-field spectra were observed by 2nd harmonic components using the lock-in detection. The spatial resolution of about 300 nm was achieved at around 1000 cm− 1 (10 μm wavelength).

A soft X-ray angle-resolved photoemission system applicable to 100 µm crystals has been developed., A system for angle-resolved photoemission spectroscopy (ARPES) of small single crystals with sizes down to 100 µm has been developed. Soft X-ray synchrotron radiation with a spot size of ∼40 µm × 65 µm at the sample position is used for the excitation. Using this system an ARPES measurement has been performed on a Si crystal of size 120 µm × 100 µm × 80 µm. The crystal was properly oriented on a sample stage by measuring the Laue spots. The crystal was cleaved in situ with a microcleaver at 100 K. The cleaved surface was adjusted to the beam spot using an optical microscope. Consequently, clear band dispersions along the Γ–X direction reflecting the bulk electronic states were observed with a photon energy of 879 eV.

Soft-x-ray-excited angle-resolved photoelectron spectroscopy studies on silicon dioxide films formed using oxygen radicals (OR) versus oxygen molecules (OM) are reported. Most of intermediate oxidation states of Si, so called suboxides, consisting of Si3+, Si2+, and Si1+ are localized at and near the SiO2/Si interfaces. The suboxides formed utilizing OM are located extremely close to the interfaces, while suboxides formed utilizing OR are located not only at the interface but also in the Si substrate. This implies the penetration of a part of OR into the Si substrate to form Si1+ and to relax the interfacial stress. Intermediate chemical bonding states of Si are formed in Si substrate closer to the interface as compared with those formed utilizing OM. This implies that the interfacial stress in the former is smaller than that in the latter.

We have developed a 25 T pulsed high magnetic field system for soft X-ray Magnetic Circular Dichroism: XMCD. The ultra-high vacuum chamber with a pulse magnet coil is installed. By using a newly developed bipolar capacitor bank, the XMCD of paramagnetic Gd2O3 at the M5 and the M4 edges was clearly observed at low temperatures. The present system is capable of measuring XMCD of field induced moments in various compounds including paramagnets and antiferromagnets.

The epitaxial silicon oxynitride (SiON) layer grown on a 6H-SiC(0001) surface is studied with core level photoemission spectroscopy. Si 2p spectra show three spectral components other than the bulk one. Chemical shifts and emission angle dependence of these components are well explained within a framework of a determined structure model of the SiON layer.

We report the results of near-field spectroscopy measurements performed using a scanning near-field optical microscopy system combined with an infrared synchrotron radiation source. The infrared synchrotron radiation is a highly brilliant white light source, and is tightly focused onto the probe tip. Strong background scattering is suppressed by modulating the distance between the probe and the sample. Higher harmonic components are extracted from the scattered light using a lock-in amplifier and examined for the presence of near-field signals. Near-field spectra in the mid-infrared region are measured by loading the higher harmonic components into a Fourier transform infrared spectroscopic apparatus. A striped metal pattern with a width of 1 μm printed on a glass substrate is found to be resolved at a wavelength of 9.8 μm. [DOI: 10.1380/ejssnt.2011.63]

The second GeV bremsstrahlung photon beamline has been constructed for meson photo-production experiments at Research Center for Electron Photon Science, Tohoku University, where a 1200 MeV electron synchrotron called STretcher Booster (STB) has been in operation primarily for Quark Nuclear Physics. An internal radiator is employed to produce the bremsstrahlung photon beam out of circulating electrons in the STB ring. A photon tagging system is placed inside one of the bending magnets of the ring. The tagged energy of the photon beam ranges from 740 to 1150 MeV for 1200 MeV operation of the STB synchrotron. The details of the tagging system and the characteristics of the photon beam are described.

The electrical ferromagnetic resonance of micro-scale Ni wires with magnetic anisotropy induced by the heterojunction between the Ni layer and ferroelectric single crystalline LiNbO3 substrate was demonstrated by using rectifying effect. The two resonance modes were observed in the Ni wire aligned parallel to the applied magnetic field in plane. The lower resonance frequency mode is considered to correspond to the normal resonance mode with domain resonance, while the higher resonance mode is attributed to the mode which is contributed by the heterojunction between the Ni layer and LiNbO3 substrate. Our results manifest that the rectifying electrical detections are very useful for understating and evaluating the magnetic properties induced by the heterojunction.

We have developed a new spin-polarized photoemission spectrometer combined a commercial hemispherical electron energy analyzer with an electron spin-polarimeter employing the very low energy electron diffraction (VLEED) at a Fe(001)p(1×1)-O surface. The new polarimeter has realized the effective Sherman function of 0.40 and the figure of merit of 1.9×10-2, which is approximately two orders of magnitude higher than that expected with a compact Mott scattering spin-polarimeter. The new system enabled us to measure spin- and angle-resolved photoemission spectra with high energy and momentum resolutions.

We have applied the spectroscopic photoemission and low energy electron microscope to study high- k gate dielectrics and have performed the following in situ operations during ultrahigh vacuum annealing: real-time observation of surface morphology and microregion photoelectron spectroscopy measurements. Changes in surface morphology and electronic states were consistent with the models previously reported in the case of HfO 2 /Si. No clear differences between void regions and nonvoid regions have been observed in microregion photoelectron spectra for poly-Si/HfO 2 /Si, regardless of phase separation in real space. These results have suggested that the initial void formation occurs in about 100-nm wide regions for both HfO 2 /Si and poly-Si/HfO 2 /Si.

We analyze the excitation of secondary electrons by hard-X-rays in subsurface layers. By studying core-excited photoelectron lines and their plasmon satellites in photoemission spectra, we show how electrons excited by hard-X-rays can carry information from deep regions deep within the sample to the surface. It is believed that the decay of high-energy photoelectrons via plasmon-loss is strongly related to the production of secondary electrons. For high-energy electrons, however, the momentum transfer to plasmons is small compared to the electron’s initial momentum, so the lateral position on the surface from which the secondary electrons are emitted is close to that of the atom initially excited by the hard-X-rays. This explains why the spatial resolution of hard-X-ray photoelectron emission microscope (HX-PEEM) images is good even if the buried interface is covered by a film with a thickness many times the inelastic mean free path of the primary electrons. This argument explains well recent HX-PEEM results.

The ultrathin oxidation of a H/Si(1 0 0) surface with microfabricated pn-junctions was studied by photoemission electron microscopy (PEEM), mirror electron microscopy (MEM) and microscopic X-ray photoelectron spectroscopy (μ-XPS). The ultrathin oxidation inverts the contrast of the junctions in PEEM images. It is found by analyzing the intensity profiles of images that the potential distribution across the pn-junctions is also inverted by the oxidation. The charging of the oxide by ultraviolet irradiation from a light source of PEEM is attributed as the cause of the inversion of the contrast shown by μ-XPS and MEM.

Direct observation of the antiferro (AF) magnetic domain structures of a NiO (0 0 1) surface is found to be possible using a spectroscopy photoelectron low-energy electron microscope (SPELEEM) and a commercial UV Hg excitation light source without using any polarizers. The principle is based on the magnetic linear dichroism (MLD) effect, where different domain contrasts are produced according to the relative angle between the antiferromagnetic axis and the linearly polarized light. The observed AF magnetic domain structures are strongly affected by both bulk AF magnetic domain structures and the stresses induced during the sample cleaving process. Moreover, the AF magnetic domain structures are found to be irreversible when the sample is heated to over its Neel temperature and then cooled. The possibility of imaging AF magnetic domain structures without using synchrotron radiation or a polarizer is attractive.

The surface spin reorientation of NiO(0 0 1) at the ferromagnetic (FM) and antiferromagnetic (AFM) interface of Fe/NiO(0 0 1) was studied by using photoemission electron microscope (PEEM) and linearly polarized X-rays. The surface spins in special domains (T 13 , T 23 ) of bare NiO(0 0 1) are found 1.9° inclining to in-plane than the bulk spin orientation, which is explained by the surface relaxation effect. As Fe deposition, the special AFM domains observed in the PEEM images become stronger at s-polarization, while they become weaker at p-polarization. The intensity change can be explained by the in-plane canting surface spins of NiO(0 0 1) due to the exchange interaction with adjacent Fe spins. Comparing the experimental intensity ratio between the s- and p-polarization ( I s / I p ) as Fe deposition and the calculated I s / I p as spin canting angle, the NiO(0 0 1) surface spins of the special domains are estimated inclining to in-plane about 6.0° but not in-plane completely due to the 7.5 ML Fe deposition. Moreover, the sudden drop of the intensity ratio I s / I p suggests a spin order transition or in-plane magnetizing vibration in Fe film at around 2 ML thickness. Selecting proper incident light angles, the surface spin orientations of all the AFM domains are possible to study.

LuFe${}_{2}$O${}_{4}$ is being actively studied in the context of an unconventional electronic ferroelectricity that appears due to charge ordering of $F\phantom{\rule{0}{0ex}}{e}^{2+}$ and $F\phantom{\rule{0}{0ex}}{e}^{3+}$ oxidation states. LuFe${}_{2}$O${}_{4}$ displays a high magneto-electric coupling, giant magnetic coercivity, and other unusual features, some of them highly controversial. In this study a group of researchers from Japan present their XMCD results in pulsed magnetic fields reaching 30 Tesla. Their technique allows them to measure valence-specific magnetization of $F\phantom{\rule{0}{0ex}}{e}^{2+}$ and $F\phantom{\rule{0}{0ex}}{e}^{3+}$ ions above and below the charge-ordering temperature and provides a unique view on the coupling between the charge and spin degrees of freedom in LuFe${}_{2}$O${}_{4}$.