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Two recent instrumental upgrades of the inelastic X-ray scattering spectrometer installed at BL11XU at SPring-8 are reported. The first one is a multianalyzer system, where we can simultaneously use three crystal analyzers aligned perpendicularly to the scattering plane. In a test measurement of polycrystalline α-PtO 2 , the inelastic spectra obtained with each respective analyzer showed a completely identical lineshape, and a slight difference (≤10%) in intensity. The system enhances the experimental efficiency, and allows for simultaneous scan at three momenta for a single-crystal sample. The second development is a polarization analyzer for the scattered photons. A pyrolytic graphite (PG) crystal is placed in front of the detector and serves as a polarization-analyzer crystal, using the (0 0 6) reflection for the Cu K -edge. We succeeded to observe clear polarization dependence in the d – d excitations of KCuF 3 .

Perovskite-type manganites exhibit various interesting phenomena arising from complex interplay among spin, charge, orbital, and lattice degrees of freedom. One such example is the keen competition between phases with different spin/charge/orbital orders. Keen competition between antiferromagnetic metal and orbital-ordered insulator is found in the slightly electron-doped regime near Mn4+ state which is stabilized by the high oxygen-pressure condition. Another one is the emergence of ferroelectricity either induced by the magnetic ordering or independently of the magnetic ordering. As the respective examples, perovskite-type YMnO3 and Sr1−xBaxMnO3 are discussed. In the YMnO3, the ferroelectric lattice distortion associated with the E-type spin order is observed for the first time. Displacement-type ferroelectricity with off-center magnetic ions is discovered for Sr0.5Ba0.5MnO3, which shows both large polarization value and strong coupling between ferroelectricity and magnetism.

Magnetic structure on SrMnO3 films has been investigated utilizing neutron magnetic scattering technique. We have succeeded in detecting a magnetic signal at (0.5 0.5 0.5) associated with G-type antiferromagnetic order. The temperature dependence of the signal intensity indicates a second-order transition with the transition temperature, T N ~ 190 K . This is a first step of our study of the magnetism in the manganite thin film system.

Resonant X-ray scattering (RXS) has been developed as a powerful technique to observe the orbital ordering in correlated electron systems. However, the scattering mechanism has been controversial, especially in K -absorption edge resonance of transition metal oxides. We have made it clear by measuring the interference terms between the resonant scattering term and the Thomson scattering term, or between the resonant terms of dipolar ( E 1) and quadrupolar ( E 2) transition processes. The results indicate that the Jahn–Teller mechanism is more responsible than the Coulomb mechanism in an e g electron system (La 0.5 Sr 0.5 MnO 3 thin films) of 3d transition metal oxide, but it is the opposite way in a t 2g electron system (YTiO 3 ) of 3d transition metal oxides and a 4f electron system (DyB 2 C 2 ).

X-ray magnetic diffraction (XMD) technique was applied to an orbital ordering compound of ferromagnetic YTiO3 for the first time. The orbital-magnetic form factor μL(k) and the spin-magnetic form factor μS(k) were independently measured by utilizing the LS separation ability of the XMD. The μL(k) was measured for ten reciprocal-lattice points. No significant values of the μL(k) were observed for most of the reciprocal-lattice points within the estimated statistical errors, which suggested quenching of the orbital moment. The μS(k) was measured for 22 reciprocal-lattice points. Fourier synthesis of the μS(k) gave the spin density distribution mS(r) in the real space. The obtained mS(r) map shows the characteristic feature of the electron distribution of 3d electron in the t2g state of a Ti atom coordinated by O2− ions, in which the electrons are distributed away from the negative O2− ions. It is concluded that the electron distribution of the 3d electron of the Ti atom, that is, the ordered orbital (or the wave function) of YTiO3 was observed in the real space by the XMD technique.

Combined with pulsed magnets, we have carried out X-ray diffraction experiments under magnetic fields above 30 T. A key technique is that we employed a very small pulsed magnet, which is readily included in a conventional X-ray diffraction system because of the small size, small required energy, and small heat production. The insulator-to-metal transition of Pr0.6Ca0.4MnO3 around 9 T and the valence transition of YbInCu4 around 26 T are shown as demonstrations.

A very small capacitor bank and miniature pulsed magnets have been developed to perform high-field synchrotron radiation experiments. A 20 T pulsed field can be generated using an energy of 1 kJ with typical pulse duration about 1 ms . Electron spin resonance experiments in millimeter wave range and high-field X-ray diffraction experiments have been done successfully.

We developed an automatic feedback control system of the crystal–melt interface position to keep the temperature at the interface constant during growth, and demonstrate its successful application to grow Ge-rich SiGe bulk crystals with uniform composition. In this system, the position of the crystal–melt interface was automatically detected by analyzing the images captured using in situ monitoring system based on charge-coupled-devices camera, and the pulling rate of the crucible was corrected at every 1 min. The system was found to be effective to keep the crystal–melt interface position during growth even when the variation of the growth rate is quite large. Especially, the interface position was kept for 470 h during growth of Ge-rich SiGe bulk crystal when we started with a long growth melt of 80 mm. As a result, a 23 mm-long Si 0.22 Ge 0.78 bulk crystal with uniform composition was obtained thanks to the constancy of the growth temperature during growth through the control of the interface position. Our technique opens a possibility to put multicomponent bulk crystal in a practical use.

Using Co L 2,3 resonant soft X-ray scattering measurement, we reveal that the magnetic orderings with q = (1/2, 0, 1/2) and (1/2, 0, 1) originate from different magnetic domains. Temperature dependence of the magnetic ordering peaks clearly shows that there is a finite difference between the transition temperatures of these magnetic orderings.

A SiGe bulk crystal with uniform composition was successfully fabricated by clarifying and controlling the growth parameters at the crystal–melt interface. An apparatus was developed for the direct in situ observation and precise control of the interface parameters such as the temperature and the position. The dynamical change of the growth rate of a SiGe bulk crystal in a temperature gradient can be known by utilizing the apparatus. The growing crystal was continuously pulled down at the pulling rate balanced to the growth rate to keep the interface temperature constant, which resulted in the excellent uniformity of the grown crystal. Our technique opened the possibility to incorporate multicomponent semiconductor substrates to the semiconductor heterostructure technology.

Transmission electron microscope (TEM) observation at room temperature of the low temperature phase of Ni2.14Mn0.86Ga shows stress-induced 5 periodicity modulation along a pseudo-[111] cubic zone axis. On cooling to 173 K, the periodicity changes to 7. In stress-free areas, a [001] zone axis with new lattice parameters for the tetragonal phase was observed. The new lattice parameters are smaller by a factor of √2 than the expected lattice parameters. A new model for the tetragonal compound Ni2MnGa and the non-stoichiometric phases was developed with the help of TEM data, X-ray powder diffraction measurements, and a computational simulation based on the X-ray powder diffraction patterns.

We have investigated the dilute effect on a typical orbital ordering system KCuF 3 by partially substituting Zn for Cu. The crystal structure has been examined as a function of Cu concentration at room temperature by X-ray diffraction. It is found that the phase transition from a tetragonal structure to a cubic one occurs with decreasing Cu concentration. This structural phase transition is confirmed to be an orbital order–disorder transition by the resonant X-ray scattering (RXS) technique.

Magnetic order of HoB 4 with Shastry–Sutherland-type Ho lattice has been studied by neutron diffraction. In HoB 4 , two magnetic phase transitions take place at T N 1 = 7.1 K and T N 2 = 5.7 K . Below T N 1 , the intensity of the magnetic satellite reflection described by Q = ( ± δ ± δ ± δ ′ ) with δ = 0.022 and δ ′ = 0.424 gradually increases together with the weak intensity of the ( 1 0 0 ) magnetic reflection. Below T N 2 , the intensity of the ( 1 0 0 ) reflection steeply increases like a first-order transition and the satellite reflection disappears. These magnetic phase transitions are similar to those of HoB 2 C 2 in which the rare-earth ions form a square lattice without geometrical frustration.

The structure and electronic properties of Cs 3 C 60 under ambient pressure were studied by X-ray diffraction (XRD) and ESR. The XRD showed that Cs 3 C 60 takes a body-centered orthorhombic structure as the main phase. No clear structural change was observed down to 9 K. The temperature dependence of the ESR peak suggested that Cs 3 C 60 exhibits a metallic behavior but no metal-insulator transition down to 1.9 K, contrary to a previous prediction.

The hetero-seeding and segregation processes in the growth of bulk crystals of GeSi alloys by the Czochralski method were investigated. Full single crystals were obtained from a melt of low Si content GeSi or pure Ge by using a Si seed while crystals grown by using a Ge seed became polycrystalline in the early stage of growth. The abrupt and gradual transition of the compositions from the Si and Ge seeds, respectively, to the grown alloy crystals were detected by means of energy dispersive X-ray spectroscopy. Segregation during the growth initiation process is discussed in terms of the unstable solidification of the growth using a Ge seed.

Recent studies of the magnetic and structural phase transitions in oxygen layers physisorbed on graphite and hexagonal boron nitride are reviewed after introducing some phase transitions of physisorbed layers. Oxygen layers physisorbed on graphite provide an ideal two-dimensional spin system. The magnetic long-range ordering in mono- and bi-layers on graphite is discussed in relation to a random exchange-field effect. The feature of melting in the multilayer region is also described in terms of surface melting. Two new phases of an oxygen monolayer on hexagonal boron nitride have been found in a low-coverage region, which can be regarded as a magnetically one-dimensional spin system. Some curious slow kinetics are observed at the phase transition between them, which may be related to a ferroelastic to a paraelastic transition caused by a sudden increase in vortex-antivortex pairs. Finally, some developments of magnetic physisorbed systems for the future are described.

We have performed resonant and non-resonant X-ray scattering on GdB 6 to investigate the two successive phase transitions at T N = ∼ 15 K and T * = ∼ 10 K . Below T N , new superlattice reflection at the wave vector [ 1 4 1 4 1 2 ] , which is the same wave vector determined by the epithermal neutron diffraction, has been observed by X-ray scattering. In the temperature region between T * and T N , it was confirmed by the polarization analyses that the superlattice reflection is due to magnetic X-ray scattering. On the other hand, interestingly, the superlattice reflection below T * is mainly due to Thomson scattering. Unlike behavior expected from usual magnetoelastic effects, the wave vector of the lattice distortion is identical to that of the magnetic structure below T * .

Gd substitution in DyB2C2 enhances the antiferromagnetic (AFM) interaction and weakens the antiferroquadrupolar (AFQ) interaction. In Dy0.8Gd0.2B2C2, two successive transitions occur. By performing resonant X-ray scattering measurements, we confirmed the AFQ ordering temperature T Q = 18.0 K and the Neel temperature T N = 19.5 K ; T N is higher than T Q in Dy0.8Gd0.2B2C2, in contrast to DyB2C2. There exists an AFM phase between T Q and T N , and the magnetic structure is described by k = [ 1 0 0 ] . This kind of AFM phase is also observed in HoB2C2 and TbB2C2, although the magnetic structures of these compounds are long-periodic ones.

We have performed a resonant magnetic X-ray scattering study on UNiGa 5 which shows an antiferromagnetic order below T N = 86 K. Resonant features are observed at both U M 4 -edge and Ga K-edge, even though Ga is normally a nonmagnetic atom. We consider that the resonance at the Ga edge originates from the orbital polarization of Ga 4p electrons which is induced by the hybridization with the U 5f electrons.

The magnetic and electronic properties of oxygen-free, single-crystal and cesium compounds of C60 have been investigated. In non-doped crystals, a remarkable effect of oxygen absorption has been observed. The resistivity increases by a factor of 104 on absorption of oxygen, while the susceptibility shows a paramagnetic increase which obeys the Curie law. More than 8% O2 per C60 molecule is absorbed reversibly at ambient pressure and temperature, and is considered to be in the form of an O2 molecule but in a little ionized state. For the oxygen-free single crystal, the impurity level energy is obtained from the temperature dependence of the resistivity as 0.26 and 0.15 eV for T>T c and T c , respectively, T c being the rotational disorder transition temperature. In Cs x C 60 ( x = 0–4.5 ), the systematic study of susceptibility, electron spin resonance and X-ray diffraction reveals the existence of the Cs1C60 phase, in addition to x = 4 and 6 phases. Cs1C60, which has the NaCl, is a metallic phase. Cs4C60 is an insulator with a paramagnetic moment of 0.7 μ B per C60 molecule and a small antiferromagnetic interaction ( θ = −5 K ). The appearance of the magnetic moment in the multivalent C60 compound suggests that electrons in the conduction band are localized owing to the correlation effect.

An inelastic X-ray scattering spectrometer on the beamline BL11XU at the SPring-8 is described. The typical energy resolution and energy transfer are 0.1–1 eV and ∼30 eV, respectively. The main aim of this spectrometer is the measurement of electronic excitations, such as charge-transfer excitation and interband transition, especially using resonant X-ray scattering. As a test experiment, the resonant X-ray scattering spectra of LaMnO3 including Mn Kβ5 emission are given.

Two y -periodic soliton solutions (i.e. the array of the localized structures in the y direction, which propagates in the x direction) to the Kadomtsev-Petviashvili equation with positive dispersion are analyzed to investigate the natures of the interactions between them. The interactions are classified into several types according to the combinations of parameters which are related to the phase shifts. It is shown that two periodic solitons can interact infinitely apart from each other and that the transverse phase shifts can occur in some regions of parameters. Detail behaviors of interactions are illustrated graphically. Two aspects, the interaction and the instability in relation to the general time evolution of the system are discussed.

An oxygen monolayer adsorbed on graphite, which is expected to be a 2D antiferromagnet, have been investigated by dc magnetic susceptibility measurements. The dense monolayer phase, in which oxygen molecules have a deformed triangular lattice with the molecular axis normal to the graphite surface, shows an anomaly at T N =11.9 K. The temperature dependence of susceptibility χ below T N suggests the presence of an antiferromagnetic long-range order, but no appreciable anisotropy of χ even below T N . The observed coverage dependence of the magnetic anomaly revealed that the first layer adjacent to graphite is responsible for the magnetic transition but the second layer does not contribute to it.

The two periodic soliton solution to the Kadomtsev-Petviashvili equation with positive dispersion is analyzed to show that the soliton resonance between them exists. It is shown that there is a parameter regime where the interactions result in a center shift of solitons not only in the direction of propagation but also in the transverse direction. The resonant interactions are associated with the parametric points on the boundary between the regime for transverse center shift and that for no transverse center shift of solitons.

Investigation on a high-Tc superconductor, La1.85Sr0.15CuO4, was performed in the wide range of Q-E space by means of neutron scattering and synchrotron radiation. The structure as well as the phonon dynamics showed a clear evolution at Tc. We found a spontaneous strain and phonon softening, which proves a strong coupling between lattice and superconductivity.

On epitaxially grown Eu-Sr superlattice films, SQUID measurements of magnetization were made. For the samples with superlattice Eu layer thicknesses of less than 2.5 nm, the Curie-Weiss law held with antiferromagnetic Weiss temperatures of minus several Kelvin, while for the samples with Eu layer thicknesses larger than 5 nm, ferromagnetic phases occurred with two step transitions at 150 and 18 K.

We report a resonant inelastic X-ray scattering (RIXS) study of charge excitations in the two-leg ladder Sr14Cu24O41. RIXS spectra at 1–5 eV are found to be dependent on temperature. An intraband excitation of the ladder, which appears as a continuum intensity below the Mott gap, decreases in intensity with temperature. Because the intraband excitation is related to the dynamics of doped holes in the ladder, its decrease of the intraband excitation is attributed to the reduction of the mobile holes in the ladder at low temperature.

A crucial effect of oxygen on resistivity ϱ of a C 60 single crystal and the temperature (160-570K) dependence of ϱ have been studied. The resistivity increases by a factor of 10 4 on absorption of oxygen; the estimated concentration is 4% O 2 eer C 60 . The processes of oxygen absorption and desorption are reversible. The activation energy in ϱ of the oxygen-free crystal is 0.26 and 0.15 eV above and below Tc = 250K , respectively, which is ascribed to an impurity level.

Pressure effects on the orbital ordered state in YVO 3 have been studied by using the low-temperature and high-pressure X-ray scattering technique. The pressure–temperature phase diagram for the orbital state was determined through the crystal structure. By applying pressure the C -type orbital ordering ( C -OO) is stabilized as compared with the G -type orbital ordering ( G -OO). It was also found that the ground state in TbVO 3 changes from the G -OO into the C -OO above ∼ 2 GPa , in common with YVO 3 .

We have investigated the field-induced coexistent phase of antiferroquadrupolar (AFQ) and antiferromagnetic order in TbB 2 C 2 by resonant X-ray scattering. Incident energy dependences of forbidden and superlattice reflections show that the field-induced AFQ order in TbB 2 C 2 is structurally the same one as in the AFQ-ordered phase of DyB 2 C 2 and HoB 2 C 2 at zero magnetic field.

We have revealed the relationship between the orbital ordering and the magnetism in the perovskite Ti oxides RTiO3 (R; rare earth elements) by using resonant X-ray scattering (RXS) near the K absorption edge of Ti. We observed the temperature dependence of the resonant signal in SmTiO3. The resonant signal hardly changed at the magnetic phase transition. Besides, the energy spectra at Q = ( 0 0 3 ) and the full width at half maximum (FWHM) for the 2 θ - ω scan are unchanged. Combining with the behavior that the periodicities of the azimuthal angle dependence for GdTiO3 and SmTiO3 are identical at each scattering vector, it is concluded that the change of the magnetism from ferromagnetic (FM) to antiferromagnetic (AFM) has little effect on the orbital ordering in RTiO3.

It has been theoretically expected that critical phenomena of helimagnetism is drastically different from those of collinear antiferromagnetism due to the existence of chiral degree of freedom. In order to verify this prediction, we carried out X-ray magnetic scattering measurements on a simplest helimagnet β-MnO2 using a synchrotron radiation. The critical exponent β was estimated at 0.25±0.05 from the temperature dependence of the scattering intensity. This value is consistent with the predicted value 0.253 for chiral system rather than with 0.346 for collinear system.

An anomalous pressure effect on the magnetic susceptibility of a spin-Peierls substance, MEM-[TCNQ] 2 , is observed. As the pressure increases, the susceptibility at low temperatures increases as if free magnetic spins are produced and it overwhelms the spin-Peierls transition. In order to clarify the pressure effect, the crystal structure of the substance under pressure has been studied by using synchrotron radiation X-rays. The reflection resulting from the superlattice of the spin-Peierls state below 18 K disappears under pressure and the crystal structure is significantly affected even at room temperature.

The 29 Si-NMR measurements on potassium-loaded zeolite LTA (K x /K 12 -Al 12 Si 12 O 48 ), where x is loaded potassium atoms per α -cage, were carried out. It was found that the NMR line-shape in the paramagnetic state is essentially the same for x =4–7, implying that the distribution and amplitude of the magnetic moment are quiet similar to each other. Possible distribution of the magnetic moment and the origin of the magnetic interactions are discussed.

The spin transition behavior of iron(II) complexes [Fe(4-NH 2 trz) 3 ](C m H 2m+1 SO 3 ) 2 · 2H 2 O (4-NH 2 trz=4-amino-1,2,4-triazole, m=1~9) was investigated by the magnetic measurement. The transition temperature T c became higher with increasing the length of alkyl chain of counter-ion, m, and saturated at m=5. The even-odd effect was observed in the hysteresis width, that is, the hysteresis width was wider for even m, narrower for odd m.

We present a new technique to synthesize high stage graphite intercalation compounds of low vapor-pressure elements such as rare earth metals (RE). The technique consists of two processes, (1) the co-intercalation of alkali-metal (AM) and RE, in which the stage is mainly controlled by vapor pressure of AM, and (2) the following de-intercalation of AM from the compound, in which the preferential removal of AM results in a high stage RE_GIC. We first obtained stages 2, 3 and 4 Eu- and stage 2 Sm-GICs. However an intercalant layer is composed of a mixture of RE and residual AM; i.e. the in-plane composition x in Eu x K 1−x -GIC was less than 0.75. The temperature dependence of magnetization of stage 3 Eu 0.75 K 0.25 -GIC shows two anomalies at T c 1 = 30 K and T c 2 = 80 K. While at T > T c2 it obeys the Curie-Weiss law with ⊗ = −15K, the magnetization process at T c1 shows remarkable metamagnetism which resembles that of stage 1 EuC 6 . The magnetic anomaly at T c2 is unique to high stage Eu compounds.

Second harmonic resonance between two marginally unstable modes is investigated in the Kelvin-Helmholtz flow. Coupled amplitude equations are obtained which depend on both time and space. Numerical integrations of the equations without spatial dependence reveal that the “explosive” instability takes place, in which both two modes grow rapidly.

High stage hetero-structure ( HS ) KMoCl 5 -graphite intercalation compounds ( GICs ) have been successfully synthesized. The stage 3 HS-GIC is deduced to have the layer sequence / MoCl 5 / K / / MoCl 5 / …, where / stands for a graphite layer. For stage 4 two kinds of HS-GICs are obtained, / MoCl 5 / K / / / MoCl 5 / … and /MoCl 5 / K / / K / MoCl 5 / …. The potassium layer enters preferentially into the graphite gallery next to the MoCl 5 layer. The Raman peaks of these HS-GICs shift from two peaks of pure K- and MoCl 5 -GICs. The results indicate that and the graphite layers next MoCl 5 and K are charged positively and negatively, respectively, and in the graphite layer between MoCl 5 and K the charge compensation occurs.

From the susceptibility and heat capacity measurements, the second stage CoCl 2 -graphite intercalation compound (GIC) is proved a good example of a two-dimensional XY-like ferromagnet. It is directly revealed by electron microscopy that each CoCl 2 plane is not extended infinitely but composed of many island-like clusters of finite size. The importance of the latter is discussed and it is concluded that the characteristic lattice structure is responsible to the successive nature of ordering in the present system.

This paper deals with the third-order resonant interaction between a quartet of linearly damped waves, one of which is continuously forced. This system has only one steady state that consist of only the forced wave. This steady state is shown to be stable both analytically and numerically. It is shown that the energy cascade from the forced wave to other resonating waves does not occur in the final stage of time evolution.

Succesive transitions of CoCl 2 -Graphite Intercalation Compound (CoCl 2 -GIC), a quasi two dimentsional (2D) system composed of finite size clusters, are investigated. Dynamical aspects of the transitions are examined in experiments on complex susceptibility χ ★( ω ) at ultralow frequencies, relaxation process of magnetization and temperature dependence of remnant magnetization Mr in series of heating and cooling processes.

A critical slowing down is observed on the staggered mode in an antiferromagnetic Co(HCOO) 2 ·2H 2 O. The characteristic frequency of the dispersion is lowest ( ≈ 20 MHz) at T N . Another low frequency dispersion mode appears below T N . These characteristic dynamical features are attributable to the non-uniform ordered structure in the present system.