[en] A new technique to measure the polarization dependence of scattering intensity without using an analyzer crystal has been developed and applied to a magnetic satellite reflection of rare-earth metal dysprosium. We have successfully observed the scattering plane inclination angle θ dependence of satellite peak intensity. The magnetic and charge scattering have definitely different θ dependence of scattering intensity, which enables us to distinguish the scattering origins

[en] The ternary intermetallic compound TbPdAl crystallizes in the hexagonal ZrNiAl-type and the orthorhombic TiNiSi-type structures. The former compound undergoes two successive antiferromagnetic transitions with the Neel temperatures of T_N1=43 K and T_N2=22 K. It is also characteristic that this compound exhibits an isostructural phase transition at around T=100 K. In this work, to investigate the origin of this transition, we have carried out extended X-ray absorption fine structures (EXAFS) and X-ray absorption near edge structure (XANES) measurements at the Tb L₃- and Pd K-edge. It was found that Fourier transforms for k³-weighted Tb L₃-edge EXAFS spectra changed below and above the transition temperature, which is consistent with the existence of the structural transition. In addition, slight temperature dependence was observed in the Pd K-edge XANES spectra, whereas the spectra at the Tb L₃-edge showed no obvious change. This result suggests that the transition is caused mainly by the change of the electronic structure of Pd

[en] Structure and magnetism have been investigated for perovskite Eu_1-xDy_xTiO₃. It is known that while EuTiO₃ (x=0) exhibits antiferromagnetism below ∼6 K, DyTiO₃ (x=1) becomes a ferrimagnet below ∼64 K. The crystal structures are assigned to be cubic and orthorhombic for x≤0.3 and x≥0.4, respectively. Magnetic transitions are observed for all the compounds. The valence of Eu is assumed to be 2+ in the solid solutions as well on the basis of inverse susceptibility data. Characteristic phenomena, such as the metallic ferromagnetism for 0.1≤x≤∼0.5, are likely due to a mixed or an intermediate valence state of Ti

[en] Magnetization measurements for Ln_0.5Sr_0.5CoO₃ (Ln=Pr, Nd, Sm and Eu and Gd) show ferromagnetic transitions with Curie temperatures (T_C) between 233 and 130 K, accompanied by spin-glass-like behavior. These compounds are metallic below T_C, which is an entirely different property from that of the corresponding Ba-systems Ln_0.5Ba_0.5CoO₃. Only Gd_0.5Sr_0.5CoO₃ shows obvious insulating behavior below ∼80 K

[en] We report a resonant X-ray diffraction and a transmission electron microscope observation on triangular layered oxide RFe₂O₄ (R=Lu and Y). The observed super structure is concluded to be originated from the charge ordering on triangular plane. The origin of the charge ordering is interpreted as the competing interaction of the charges between nearest and next nearest neighbor charges on triangular lattice

[en] Two prototypes of a one-dimensional microstrip germanium detector were fabricated with seven strips, having different pitches of 200 and 350 μm. Owing to its insensitivity to hole-diffusion process, the latter one has attained a spatial resolution as high as 350 μm, an energy resolution better than 1.4%, and a peak efficiency around 50% at an X-ray energy of 80 keV

[en] A new X-ray spectrometer has been installed in the BL08W beamline at SPring-8 for high-resolution Compton scattering measurements using 90-120 keV X-rays. The spectrometer consists of a Cauchois-type triple-crystal analyzer and a quasi position sensitive detector with four slits. The detector works not only as a position-sensitive detector but also as an energy sensitive detector, which allows for low background noise measurements. An overall resolution of 0.10 atomic units in momentum space has been achieved at the incident X-ray energy of 115 keV. Compton profiles of niobium have been measured along the [1 0 0] and [1 1 0] directions in order to demonstrate the performance of the spectrometer

[en] A 128-channel microstrip Germanium detector system has been developed to efficiently detect Compton-scattered X-rays and to effectively reject the background X-rays associated in the Compton spectrometer of the high-energy inelastic scattering beamline at the SPring-8 facility. In order to handle the large number of the readout channels, four 32-parallel-input front-end hybrid boards have been adopted as charge-sensitive pre-amplifiers and discriminators, which are currently controlled by a Windows-based PC data-acquisition system

[en] Compton-scattering experiment with a SR X-ray beam in high energy region offers a direct access to the electron momentum distributions in various substances, and the high energy inelastic scattering beamline (BL08W) of the SPring-8 facility embodies this straightforward experimental method. This paper describes the detector characterization carried out in various aspects, and reports the first experimental results obtained with the high energy X-ray beam at the BL08W. The X-ray energy spectra for the ⁵⁷Co X-ray source with the detector No.1 and No.2 both operated with their nominal voltages are observed. With respect to the main peak of 121 KeV, the energy resolution (fwhm) that observed in these detectors is 1.62 keV and 1.47 keV with No.1 and No.2, respectively. The efficiencies observed in No.1 and No.2 increase with increasing Vap. With applying Vap = 1000 and 2000 volts, the peak efficiencies of No.1 and No.2 become 13 % and 30 %, respectively. This means that the nominal operation voltages are not sufficiently high to suppress diffusion process for the prototypes, and strongly suggests that the values of σ_trans in the prototypes are much larger than those calculated from the model. Similar results have been also obtained with the ²⁴¹Am source. It has become clear from the present work that the hole diffusion processes are much more enhanced than anticipated. Since the prototype with the microstrip pitch of 350 μm is less subject to this process, it has attained a spatial resolution as high as 350 μm with an energy resolution better than 1.4 % and with an overall detection efficiency higher than 50 % at an X-ray energy of 80 keV. (S.Y.)

[en] We investigated the electronic structure of SmNiC₂ by using X-ray absorption spectroscopy (XAS) and magnetic circular dichroism (MCD). The XAS and MCD measurements were performed around Sm L_2,3-edges and Ni K-edge. The element selective magnetic hysteresis curves were measured around Sm L_2,3-edges and Ni K-edge. The XAS spectrum showed a single peak around Sm L_2,3-edges. The valence of Sm ions in SmNiC₂ is a little smaller than trivalent. The MCD signals were clearly observed around all absorption edges below the Curie temperature. We concluded that Ni atoms in SmNiC₂ have a finite magnetic moment by analyzing the spectrum at Sm L₃-edge. The shape of ESMH loops were different from the hysteresis loop measured by a SQUID magnetometer. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)