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Titanium disulfide TiS$_2$, which is a member of the layered transition-metal dichalcogenides with the 1T-CdI$_2$-type crystal structure, is known to exhibit a wide variety of magnetism through intercalating various kinds of transition-metal atoms of different concentrations. Among them, Fe-intercalated titanium disulfide Fe$_x$TiS$_2$ is known to be ferromagnetic with strong perpendicular magnetic anisotropy (PMA) and large coercive fields ($H_\text{c}$). In order to study the microscopic origin of the magnetism of this compound, we have performed X-ray absorption spectroscopy (XAS) and X-ray magnetic circular dichroism (XMCD) measurements on single crystals of heavily intercalated Fe$_x$TiS$_2$ ($x\sim0.5$). The grown single crystals showed a strong PMA with a large $H_\text{c}$ of $\mu_0H_\text{c} \simeq 1.0\ \text{T}$. XAS and XMCD spectra showed that Fe is fully in the valence states of 2+ and that Ti is in an itinerant electronic state, indicating electron transfer from the intercalated Fe atoms to the host TiS$_2$ bands. The Fe$^{2+}$ ions were shown to have a large orbital magnetic moment of $\simeq 0.59\ \mu_\text{B}\text{/Fe}$, to which, combined with the spin-orbit interaction and the trigonal crystal field, we attribute the strong magnetic anisotropy of Fe$_x$TiS$_2$., Comment: 24 pages, 8 figures

Perpendicular magnetic anisotropy of the new ferromagnetic semiconductor (Ba,K)(Zn,Mn)$_{2}$As$_{2}$ is studied by angle-dependent x-ray magnetic circular dichroism measurements. The large magnetic anisotropy with the anisotropy field of 0.85 T is deduced by fitting the Stoner-Wohlfarth model to the magnetic-field-angle dependence of the projected magnetic moment. Transverse XMCD spectra highlights the anisotropic distribution of Mn 3$d$ electrons, where the $d_{xz}$ and $d_{yz}$ orbitals are less populated than the $d_{xy}$ state because of the $D_{2d}$ splitting arising from the elongated MnAs$_{4}$ tetrahedra. It is suggested that the magnetic anisotropy originates from the degeneracy lifting of $p$-$d_{xz}$, $d_{yz}$ hybridized states at the Fermi level and resulting energy gain due to spin-orbit coupling when spins are aligned along the $z$ direction.

Spinel-type CoFe$_2$O$_4$ is a ferrimagnetic insulator with the N\'eel temperature exceeding 790 K, and shows a strong cubic magnetocrystalline anisotropy (MCA) in bulk materials. However, when a CoFe$_2$O$_4$ film is grown on other materials, its magnetic properties are degraded so that so-called magnetically dead layers are expected to be formed in the interfacial region. We investigate how the magnetic anisotropy of CoFe$_2$O$_4$ is modified at the interface of CoFe$_2$O$_4$/Al$_2$O$_3$ bilayers grown on Si(111) using x-ray magnetic circular dichroism (XMCD). We find that the thinner CoFe$_2$O$_4$ films have significantly smaller MCA values than bulk materials. The reduction of MCA is explained by the reduced number of Co$^{2+}$ ions at the $O_h$ site reported by a previous study [Y. K. Wakabayashi $\textit{et al.}$, Phys. Rev. B $\textbf{96}$, 104410 (2017)]., Comment: 5 pages, 3 figures

We have investigated the orbital states of the orbital-glassy (short-range orbital ordered) spinel vanadate Co$_{1.21}$V$_{1.79}$O$_{4}$ using x-ray absorption spectroscopy (XAS), x-ray magnetic circular dichroism (XMCD), and subsequent configuration-interaction cluster-model calculation. From the sign of the XMCD spectra, it was found that the spin magnetic moment of the Co ion is aligned parallel to the applied magnetic field and that of the V ion anti-parallel to it, consistent with neutron scattering studies. It was revealed that the excess Co ions at the octahedral site take the trivalent low-spin state, and induce a random potential to the V sublattice. The orbital magnetic moment of the V ion is small although finite, suggesting that the ordered orbitals mainly consists of real-number orbitals., 7 pages, 6 figures

Magnetic anisotropies of ferromagnetic thin films are induced by epitaxial strain from the substrate via strain-induced anisotropy in the orbital magnetic moment and that in the spatial distribution of spin-polarized electrons. However, the preferential orbital occupation in ferromagnetic metallic La$_{1-x}$Sr$_x$MnO$_3$ (LSMO) thin films studied by x-ray linear dichroism (XLD) has always been found out-of-plane for both tensile and compressive epitaxial strain and hence irrespective of the magnetic anisotropy. In order to resolve this mystery, we directly probed the preferential orbital occupation of spin-polarized electrons in LSMO thin films under strain by angle-dependent x-ray magnetic circular dichroism (XMCD). Anisotropy of the spin-density distribution was found to be in-plane for the tensile strain and out-of-plane for the compressive strain, consistent with the observed magnetic anisotropy. The ubiquitous out-of-plane preferential orbital occupation seen by XLD is attributed to the occupation of both spin-up and spin-down out-of-plane orbitals in the surface magnetic dead layer., Comment: 20 pages, 4 figures

Magnetic anisotropy of epitaxially grown thin films is affected by the strain from the substrates due to a combined effect of distorted electronic structure and spin-orbit interaction (SOI). As an inverse process, one expects an anisotropy of the electronic structure induced by magnetization in the presence of SOI. We have studied the charge-density anisotropy induced by magnetization in thin films of the ferromagnetic metal La$_{1-x}$Sr$_{x}$MnO$_3$ via x-ray magnetic linear dichroism (XMLD). XMLD measurements on thin films with various thicknesses have shown that the XMLD intensity is proportional to the square of the ferromagnetic moment. Using the XMLD sum rule and cluster-model calculation, it has been shown that more Mn 3$d$ electrons are distributed in orbitals elongated along the direction parallel to the spin polarization than in orbitals elongated in the direction perpendicular to it. The cluster-model calculation has shown that the effect of tensile strain from the SrTiO$_3$ substrate on the XMLD spectra is also consistent with the observed XMLD spectral line shapes., Comment: 12 pages, 4 figures

We have studied the electronic and magnetic states of Co and Mn atoms at the interface of the Co$_\mathrm{2}$Mn$_{\beta}$Si (CMS)/MgO ($\beta$=0.69, 0.99, 1.15 and 1.29) magnetic tunnel junction (MTJ) by means of x-ray magnetic circular dichroism. In particular, the Mn composition ($\beta$) dependences of the Mn and Co magnetic moments were investigated. The experimental spin magnetic moments of Mn, $m_\mathrm{spin}$(Mn), derived from XMCD weakly decreased with increasing Mn composition $\beta$ in going from Mn-deficient to Mn-rich CMS films. This behavior was explained by first-principles calculations based on the antisite-based site-specific formula unit (SSFU) composition model, which assumes the formation of only antisite defect, not vacancies, to accommodate off-stoichiometry. Furthermore, the experimental spin magnetic moments of Co, $m_\mathrm{spin}$(Co), also weakly decreased with increasing Mn composition. This behavior was consistently explained by the antisite-based SSFU model, in particular, by the decrease in the concentration of Co$_\mathrm{Mn}$ antisites detrimental to the half-metallicity of CMS with increasing $\beta$. This finding is consistent with the higher TMR ratios which have been observed for CMS/MgO/CMS MTJs with Mn-rich CMS electrodes., Comment: 6 Pages, 4 figures, Submitted in J. Appl. Phys

We have studied the magnetic states of Au/2-monolayer Co clusters/Au(1 1 1) by angle-, field-, temperature-, and cluster-size-dependent magnetic circular X-ray dichroism (MCXD) measurements in the longitudinal geometry with full use of a magic angle of 54.7°. The absolute magnitude of the normal-incidence MCXD provides evidence for a single domain of clusters and for a phase transition from ferromagnetism (FM) to superparamagnetism (SPM) with decreasing cluster size. The spin, in-plane and out-of-plane orbital, and in-plane and out-of-plane magnetic dipole moments of almost purely interfacial Co atoms were directly determined. The interfacial spin moment is strongly enhanced and the interfacial orbital and magnetic dipole moments are highly anisotropic and enhanced as compared with those in bulk Co, verifying theoretical predictions. We argue the implications of the results in particular relation to their physical origin and to a potential technological application of the nanoclusters.

N K -, O K - and Co L III,II -edge X-ray magnetic circular dichroism (XMCD) was investigated for NO adsorbed on ultrathin fcc -Co(001) films which show both in-planar and perpendicular magnetic anisotropies. Large suppression of spin and orbital magnetic moments of Co was observed upon NO adsorption. Both N and O K -edge XMCD spectra show negative signs at the NO 2π * resonance, irrespective of in-plane and perpendicular magnetic anisotropies. This finding implies the parallel alignment of the NO 2π * orbital magnetic moments with the total magnetization. The results are comparatively discussed with the previous works on CO on Co and Ni films and are interpreted by a simple chemical bonding scheme.

We have measured the temperature dependence of MCD spectra on Ce@C82 and Ce2@C80 in the Ce 3d–4f excitation region. The results show that Ce@C82 has antiferromagnetic interaction while Ce2@C80 has ferromagnetic interaction between Ce magnetic moments which are much smaller than the Hund-ground-state values.

Metallic transition-metal oxides undergo a metal-to-insulator transition (MIT) as the film thickness decreases across a critical thickness of several monolayers (MLs), but its driving mechanism remains controversial. We have studied the thickness-dependent MIT of the ferromagnetic metal ${\mathrm{La}}_{0.6}$${\mathrm{Sr}}_{0.4}$${\mathrm{MnO}}_{3}$ by x-ray absorption spectroscopy and x-ray magnetic circular dichroism. As the film thickness was decreased across the critical thickness of the MIT (6--8 ML), a gradual decrease of the ferromagnetic signals and a concomitant increase of paramagnetic signals were observed, while the Mn valence abruptly decreased towards ${\mathrm{Mn}}^{3+}$. These observations suggest that the ferromagnetic phase gradually and most likely inhomogeneously turns into the paramagnetic phase and both phases abruptly become insulating at the critical thickness.

The electronic structure of the ferromagnetic transition-metal oxide SrRuO3 has been studied by magnetic circular dichroism (MCD) in the valence-band photoemission spectra. MCD signals have been obtained by changing the direction of sample magnetization as well as the helicity of incident photons. Strong MCD signals were observed near the Fermi level. We have attempted to explain the MCD spectra using a band structure calculated with the unrestricted Hartree–Fock method.

Magnetic-circular-dichroism (MCD) spectra have been obtained at and around the Fe M2,3 and Co M2,3 core-absorption edges in ferrimagnetic Fe3O4 and CoFe2O4. For Fe3O4, a comparison is also made between the M2,3 prethreshold MCD spectra taken above and below the Verwey transition temperature (∼ 120 K). The results are interpreted in terms of reported band-structure calculations and the atomic model, with particular attention given to the MCD at the Fe M2,3 prethreshold multiplets.

The magnetic circular dichroism (MCD) spectra in the exciton region of KBr and RbBr were measured for the first time utilizing an ultrahigh-vacuum compatible superconducting magnet system. The obtained effective g values (geff) at the fundamental exciton peaks are well explained as being a spin-orbit pair at the Γ point. Negative geff values in the following higher energy regions suggest the involvement of a d-like character at related conduction bands.

Magnetic circular dichroism (MCD) has been observed at the Fe L2,3 and M2,3 core-absorption edges in ferrimagnetic Fe7S8 and Fe7Se8 using circularly polarized helical undulator radiation. Some differences were observed between the MCD spectra of both compounds. The features of the MCD spectra are interpreted on the basis of a reported band-structure calculation.

Magnetic circular dichroism (MCD) has been observed at the Co L2,3 and M2,3 core-absorption edges in a single crystal of ferromagnetic CoS2 using circularly polarized helical undulator radiation. The features in the MCD spectra are interpreted on the basis of reported band-structure calculations. By applying the MCD sum rules to the L2,3 MCD spectrum, we obtained a ratio of the orbital-to-spin magnetic moments of 0.14.

We have studied the local magnetic states of a single-crystalline Fe film, annealed and as-deposited Fe-Pt alloy films, and an Fe/Pt multilayer by magnetic circular dichroism (MCD) in core-level absorption. The MCD spectra around the Fe ${\mathit{M}}_{2,3}$ edges unambiguously reveal an enhanced 3d orbital moment in the alloys and multilayer relative to that in Fe metal. MCD signals were also observed at the Pt ${\mathit{N}}_{6,7}$ and ${\mathit{O}}_{2}$ edges in the alloys and multilayer, showing induced magnetic moments on Pt atoms. A comparison of the MCD spectral pattern at the Pt ${\mathit{N}}_{6,7}$ edges with that at the Fe ${\mathit{M}}_{2,3}$ and Pt ${\mathit{O}}_{2,3}$ edges gives clear evidence that the induced Pt moments are aligned parallel to the Fe moments. Fine MCD features observed at the Pt ${\mathit{N}}_{6,7}$ edges indicate that the Pt 5d partial density of states just above the Fermi level is higher for the majority-spin states than for the minority-spin states. \textcopyright{} 1996 The American Physical Society.

Polarization measurements have been performed using a reflection polarimeter in the 50–80 eV region for elliptically polarized synchrotron radiation from a helical undulator installed on beamline BL-28 at the Photon Factory. The degree of circular polarization (PC) was found to strongly depend on the photon energy, indicating the importance of a correction for PC in applications of the undulator radiation. The measured Stokes parameters were compared with numerical calculations. The results are discussed in relation to the effects on the polarization of the beamline optics and of the mixing of the bending-magnet radiation.

A magnetic field modulation apparatus has been designed and constructed for magnetic‐circular‐dichroism (MCD) studies beyond the LiF transmission cutoff in the vacuum‐ultraviolet and soft x‐ray regions. The magnet is a split‐coil solenoid, immersed in liquid nitrogen in order to reduce its Ohmic loss, and can produce alternating magnetic fields of up to 5.5 kG rms at moderate frequencies (∼5 Hz). The clear bore of the magnet is 40 mm in diameter, enabling measurements in both reflection and transmission configurations. The entire apparatus is bakable up to 150 °C in order to make it ultrahigh‐vacuum compatible. This apparatus, together with our recently developed triple‐reflection circular polarizer, provides a powerful tool for detecting very small MCD signals (∼10−5) by a modulation technique, even on the existing beam lines.

An ultrahigh‐vacuum compatible 5.8‐T superconducting magnet system has been designed and constructed for use in magnetic circular dichroism (MCD) and magnetic‐imaging photoemission‐spectromicroscopy (MIPESM) studies. The design considerations and technical details of the cryosystem which is used to enable bakeouts, along with the magnet performance, are described. The experimental setups of the established MCD measurements and the planned MIPESM measurements are presented. An example of the obtained MCD spectra is also given.

The combined utilization of directly characterized off‐plane circularly polarized synchrotron radiation and an ultrahigh‐vacuum compatible superconducting magnet has enabled magnetic‐circular‐dichroism (MCD) experiments, mainly at the M2,3 core absorption edges. Details concerning the experimental technique, which allowed quantitative MCD measurements, are described. The results are presented and discussed for single crystals of Ni, Fe, and Fe3O4, and an Fe/Pt multilayer.

A complete polarization analysis has been successfully achieved for synchrotron radiation beams in the vacuum ultraviolet and soft x‐ray regions using a reflection polarimeter. The Stokes parameters, which provide a full description of the polarization state of light, were experimentally determined along with three polarizing quantities of the polarimeter. The present result indicates the possibility of a simultaneous determination of the optical constants of mirror materials through polarization analyses.

An ellipsometer has been designed and constructed for use in the vacuum ultraviolet region. To test the performance of the ellipsometer, the optical constants of Au were determined in the energy region 15–28 eV. The theoretical background and the experimental procedures of our ellipsometer are described.

The Stokes parameters, which completely represent the polarization state of light, have been measured in the 5–80-eV energy region for synchrotron-radiation beams on the VUV to soft X-ray beamlines at the Photon Factory. Various states of polarization were produced for the emerging beam by deflecting the incoming beam vertically with respect to the entrance slit of the monochromator with a premirror of the beamline. The resultant beam was polarization-analyzed using a polarimeter comprising two triple-reflection polarizers. Increasing the beam-deflection angle was found to result in a change in the polarization state from predominantly horizontal linear polarization to elliptical polarization. This procedure could be used both to produce and to verify circular polarization with | P c | ≳ 80% in the energy range 60–80 eV, which could be immediately applied to MCD experiments. Unpolarized light could clearly be distinguished from circularly polarized light. The unpolarized component was found to become larger with increasing energy on a soft X-ray beamline; this was shown to be mainly due to scattering by beamline optical elements.

Magnetic-circular-dichroism (MCD) spectra have been obtained at and around the ${\mathit{M}}_{2,3}$ core absorption edges in single crystals of ferromagnetic Ni and ferrimagnetic ${\mathrm{Fe}}_{3}$${\mathrm{O}}_{4}$. Furthermore, strong MCD signals were observed for the weak multiplet structures of ${\mathrm{Fe}}_{3}$${\mathrm{O}}_{4}$ in the prethreshold region. The experiments were performed using a bulk-sensitive reflection method by utilizing directly characterized, circularly polarized synchrotron radiation in conjunction with an ultrahigh-vacuum-compatible, i.e., bakable, superconducting magnet of interesting design. The present observation of a strong MCD not only provides a sensitive method for probing the local magnetic states of magnetic substances, but also could provide valuable information concerning the 3d electronic states of these materials.

The 3 p -XPS and the 3 d -XPS of LaAl 2 CeAl 2 and CeRu 2 are measured using undulator radiation at the Photon Factory. The obtained data are analyzed satisfactorily with the use of the impurity Anderson model. From the analysis for CeRu 2 , the 3 p and 3 d core-hole potentials acting on 4 f electrons are found to be almost the same.

The stoichiometry-dependent bulk electronic structure has been studied by optical spectroscopy for single crystals of ${\mathrm{TiC}}_{\mathit{x}}$ with x=0.95 and 0.70, ${\mathrm{VC}}_{\mathit{x}}$ with x=0.86 and 0.76, and ${\mathrm{NbC}}_{\mathit{x}}$ with x=0.93, 0.84, and 0.71. The reflectance was measured in the energy range 0.5--40 eV for all of the samples and up to 100 eV for ${\mathrm{TiC}}_{0.95}$, ${\mathrm{VC}}_{0.86}$, and ${\mathrm{NbC}}_{0.93}$. By correcting for the surface-roughness effect using the measured roughness values, the data were Kramers-Kronig analyzed to obtain the dielectric function and related functions. The observed interband transitions have been interpreted on the basis of existing calculations for the energy-band structure and partial density of states. The main peaks above 4 eV were assigned to transitions at and around the X and Q portions in the Brillouin zone. Their shifts to lower energy and reduced intensities with decreasing carbon concentration are discussed in terms of p-d hybridization. Features arising from transitions involving the initial or final states near the Fermi level were observed in the low-energy region.Their dramatic stoichiometry-dependent behavior provides clear experimental evidence that the Fermi level moves downward in ${\mathrm{VC}}_{\mathit{x}}$ and ${\mathrm{NbC}}_{\mathit{x}}$ with lowering carbon content. A structure that develops remarkably in intensity as x decreases appears around 2 eV in ${\mathrm{VC}}_{\mathit{x}}$ and ${\mathrm{NbC}}_{\mathit{x}}$, while no counterpart is discern- ible in ${\mathrm{TiC}}_{\mathit{x}}$. This feature can be attributed to a transition between vacancy-induced states with ${\mathit{a}}_{1\mathit{g}}$ and ${\mathit{t}}_{1\mathit{u}}$ symmetries. The contribution of the metal p state to the optical spectra is discussed in relation to both the intrinsic peaks and the vacancy-induced feature. The electron-energy-loss functions show distinct plasmon structures that weaken and shift to lower energy with decreasing x. The main volume plasmon peak is close to the free-electron-gas plasmon energy. A small Drude plasma structure has been observed at 2.7 eV in ${\mathrm{NbC}}_{0.93}$, being rapidly attenuated with increasing carbon vacancies.

The finite-element method was used to calculate a rise in temperature at a fast-closing valve (FCV) blade during exposure to intense synchrotron radiation from a 53-pole wiggler at the 2.5-GeV Photon Factory storage ring. The results indicate a possible meltdown of the titanium-alloy blade within 0.1 s at a maximum beam current of 500 mA, making the vacuum protection function of the FCV ineffective for an instantaneous vacuum failure downstream of the wiggler beam line. In order to prevent the blade from melting, the FCV control system has been interlocked with RF klystrons so as to initiate blade closure after dumping the electron beam by turning off the RF power. Performance tests have shown that the system could dump the electron beam within 95 mu s and then close the blade within 12.4 ms after being triggered. >

Epitaxial multilayers with structure of bcc-Co(001)(6 ML)/bcc-Fe(001)(1 or 2 ML)/MgO(001)(20 /spl Aring/) were prepared by using molecular beam epitaxy (MBE) with in-situ RHEED observation. Magnetic moments of the 1 and 2 ML-Fe layers evaluated using the sum rules from the energy integration of the XAS and XMCD spectra were found to be considerably higher than that of bulk Fe.

Tunnel magnetoresistance (TMR) effect attracts much attention. Magnetic tunnel junctions (MTJs) with an amorphous Al-O tunnel barrier show large magnetoresistance ratio up to 70%. The orbital and spin moments of the 1 ML-Co(001) facing Al-O barrier, Al and Au metal layers were evaluated using X-ray magnetic circular dichroism (XMCD). X-ray absorption spectroscopy (XAS) was used to evaluate the oxidization state of the 1 ML-Co [001]. XAS and XMCD of the samples were measured from 635 to 855 eV. XAS data of the samples showed absence of oxidization in ML-Co layer. This indicates that the oxidization process of top Al layer was terminated without oxidizing the Co layer. The magnetic moments of 1 ML-Co was found larger than that of bulk Co indicating also that the Co layer adjacent to Al-O barrier is not oxidized.

A vacuum‐compatible reflection polarimeter has been designed and constructed for monitoring the polarization state of circularly polarized radiation from a helical undulator installed on beamline BL‐28A at the Photon Factory. The rotational axis of the polarimeter can be adjusted to coincide with the axis of the monochromatized beam. The polarimeter was used to measure the Stokes parameters of the beam emerging from BL‐28A at given energies in the 50–80 eV region with the first‐harmonic‐peak energy of undulator radiation kept at ∼75 eV. Numerical calculations were also made by considering the undulator‐radiation characteristics and further by taking into account the effects on the polarization of the beamline optics and of the mixing of bending‐magnet radiation. Comparison of the experimental results with the calculations is given.

We have measured linear and magnetic circular dichroism in the Ce 4d X-ray absorption spectra of CeRh3B2, which has a highly anomalous ferromagnetic state. The result indicates an unusually large axial crystal field of order 0.1–0.2 eV along the hexagonal c-axis.

The effect of energetic cluster ion beam irradiation on magnetic and structural properties of FeRh thin films have been investigated. The cluster ions used in the present studies consist of a few gold atoms with the energy of 1.67 MeV/gold atom. Saturation magnetization of the sample irradiated with Au3 cluster ion beam (280 emu/cc) is larger than that for the irradiated sample with Au1 ion beam (240 emu/cc) for the same irradiation ion fluence. These results can also be confirmed by the X-ray magnetic circular dichroism (XMCD) measurement; the XMCD signal for Au3 cluster ion irradiation is larger than that for Au1 ion irradiation. Since the ion beam irradiation induced magnetization of FeRh is significantly correlated with the amount of the lattice defects in the samples, cluster ion beam irradiation can be considered to effectively introduce the lattice defects in B2-type FeRh rather than the single ion beam. Consequently, cluster ion irradiation is better than single ion irradiation for the viewpoint of saturation magnetization, even if the same irradiation energy is deposited in the samples.

The conversion of linearly polarized synchrotron radiation to circular polarization has been successfully achieved beyond the LiF transmission cutoff in the vacuum ultraviolet by utilizing a triple‐reflection polarizer as a quarter‐wave retarder. The Stokes parameters of the emerging beam were directly measured at 30 eV with a reflection‐type polarimeter as a function of the rotation angle of the ‘‘circular polarizer’’ around the optical axis. The results show that a degree of circular polarization of up to ∼±82% was attained at ∼±25° rotation angles, respectively, between the incidence plane for the polarizer and the horizontal plane. This result is in good agreement with a calculation which took into account the independently measured Stokes parameters of the incoming beam.

In this study, we developed a two-dimensional vector magnet with Y-Ba-Cu-O (YBCO) tape conductors for use in an X-ray magnetic circular dichroism measurement system. The characteristics of this high- Tc superconducting vector magnet are as follows: (a) it is a split magnet comprising four unit coils that enable an X-ray magnetic circular dichroism system to access the center sample space along three axes; (b) it is compact with a high magnetic field, and it exhibits a cone-shaped design to enable the split unit coils to come close together and to achieve a maximum magnetic field up to 1 T at the center; and (c) it is conduction-cooled by a cryocooler and a cryogen-free system. We fabricated four unit coils with YBCO tape conductors (manufactured by SuperPower Inc.). Two pairs of the unit coils were configured at right angles to each other in a cryostat and cooled below 30 K by the cryocooler. We confirmed that the magnetic field orientation can be controlled by adjusting the current of the unit coils. However, we observed hysteresis and drift of the magnetic field owing to the screening current induced in the YBCO tape conductors. Here, we design a high- Tc superconducting vector magnet and present its excitation test results.

Recent development in fast polarization switching at the soft X-ray beamline, BL-16A in the Photon Factory is reported. Two APPLE-II type undulators installed in a tandem configuration enables us to achieve polarization switching between not only two opposite circular polarizations, but also the vertical and horizontal linear polarizations. An energy shift is observed during polarization switching due to a vertical modulation in the electron beam, which has been reduced by properly correcting the electron orbit.

We have studied the electronic state of a Co(0 0 1) monatomic layer facing an amorphous-Al2O3 tunneling barrier using X-ray absorption spectroscopy (XAS) and X-ray magnetic circular dichroism (XMCD) measurements at the Co L2,3 edges. XAS and XMCD measurements evidence that the 1-ML Co facing Al2O3 layer is not oxidized.

The molecular orientation of NO and N2O during adsorption on Ir(111) is observed by combining the wavelength-dispersive x-ray absorption spectroscopy with 1 Hz switching between the vertical and horizontal linear polarizations. It is revealed that NO adsorbs keeping its molecular axis at ∼20° from surface normal. In contrast, N2O rapidly adsorbs up to 2/3 of the saturation coverage with an orientation angle of ∼35°, then turns to a slow adsorption phase with larger orientation angles, and gradually reaches its saturation with an average orientation angle of ∼45°. Such a complicated behavior is interpreted by assuming different adsorption sites.

The optical and magneto-optical properties of as-deposited and annealed ${\mathrm{Fe}}_{51}$${\mathrm{Pt}}_{49}$ films were investigated in the photon energy range 1.55--10.5 eV. The magneto-optical Kerr rotation (${\mathrm{\ensuremath{\theta}}}_{\mathrm{K}}$) spectra of both films were found to show a dispersion-type structure in the 4.6--7.8 eV region: they have large negative and broad positive peaks at around 4.8 and 7.8 eV, respectively. The ${\mathrm{\ensuremath{\theta}}}_{\mathrm{K}}$ spectra showed a tendency that is essentially quite similar to that of bulk Fe. The Kerr ellipticity (${\mathrm{\ensuremath{\eta}}}_{\mathrm{K}}$) spectra are bell shaped, exhibiting a large negative peak at 6.3 eV. Plasma edges were observed at 6.9 eV for the as-deposited film and at 7.3 eV for the annealed film. The absolute value of the real part of the off-diagonal dielectric element (${\mathrm{\ensuremath{\varepsilon}}}_{\mathrm{XY}}^{\ensuremath{'}}$) of both films at \ensuremath{\sim}4.8 eV are almost the same as that of bulk Fe. This leads to the conclusion that the ${\mathrm{\ensuremath{\theta}}}_{\mathrm{K}}$ enhancement at 4.8 eV is mainly due to a decrease in ${\mathrm{\ensuremath{\varepsilon}}}_{\mathrm{XX}}^{\mathrm{\ensuremath{''}}}$ and a peak shift in ${\mathrm{\ensuremath{\varepsilon}}}_{\mathrm{XY}}^{\ensuremath{'}}$ towards lower energy, but not to a plasma-resonance effect.

The disappearance of the Cr magnetization in the ferromagnetic Cr-doped manganites has been observed both by magnetic circular X-ray dichroism (MCD) and magnetization measurements. LaCr0.33Mn0.67O3 samples have been prepared by standard solid state reaction. The samples are ferromagnetic, whereas in the MCD measurements we observed magnetic moments only for Mn. Magnetization measurement also suggests the disappearance of the Cr magnetization.

The electronic and magnetic states of an epitaxially grown full-Heusler alloy Co2MnSi (CMS) 1.1 nm (4 ML) thick ultrathin film and a CMS 50‐nm-thick film both facing an epitaxial MgO(001) tunnel barrier were element-specifically studied by means of x-ray absorption spectroscopy (XAS) and x-ray magnetic circular dichroism (XMCD). The observed XAS and XMCD spectra revealed that both the CMS films were not oxidized. The Co and Mn spin magnetic moments for the 4 ML thick CMS film obtained by applying the sum rules were close to those for the 50‐nm-thick one and the theoretical values for bulk CMS with the L21 structure. These results indicate that 4 ML thick CMS ultrathin films facing a MgO barrier still retain the electronic and magnetic states for the L21 structure.

We element specifically studied the electronic and magnetic states of epitaxially grown full-Heusler alloy Co2MnSi (CMS) 1.1 nm (4 ML) thick ultrathin films facing an epitaxial MgO(001) tunnel barrier by means of x-ray absorption spectroscopy (XAS) and x-ray magnetic circular dichroism (XMCD). In situ reflection high-energy electron-diffraction observations indicated that the CMS films grew into the L21 structure. The observed XAS and XMCD spectra revealed that the CMS ultrathin film was not oxidized. The ratio of Mn and Co spin magnetic moments obtained by applying the sum rules was about 2.7, close to a theoretical value of 2.8 for CMS with the L21 structure.