Samarakoon, A. M.*; 高橋 満*; Zhang, D.*; Yang, J.*; 片山 尚幸*; Sinclair, R.*; Zhou, H. D.*; Diallo, S. O.*; Ehlers, G.*; Tennant, D. A.*; et al.
Scientific Reports (Internet), 7(1), p.12053_1 - 12053_8, 2017/09
Glassiness is ubiquitous and diverse in characteristics in nature. Understanding their differences and classification remains a major scientific challenge. Here, we show that scaling of magnetic memories with time can be used to classify magnetic glassy materials into two distinct classes. The systems studied are high temperature superconductor-related materials, spin-orbit Mott insulators, frustrated magnets, and dilute magnetic alloys. Our bulk magnetization measurements reveal that most densely populated magnets exhibit similar memory behavior characterized by a relaxation exponent of (1). This exponent is different from of dilute magnetic alloys that was ascribed to their hierarchical and fractal energy landscape, and is also different from of the conventional Debye relaxation expected for a spin solid, a state with long range order.
松浦 直人*; 川村 奨*; 藤田 全基*; 梶本 亮一; 山田 和芳*
Physical Review B, 95(2), p.024504_1 - 024504_6, 2017/01
Inelastic neutron scattering measurements of magnetic excitations in hole-doped high- cuprates LaSrCuO ( and 0.075) have been performed over a wide temperature range of 5 500 K extending beyond the pseudogap temperature of 360 K for . For , the two-dimensional spin-wave excitations at low temperatures are thermally robust and the dispersion is slightly softened on heating up to K. For , the spin-wave-like excitations in the upper part of the hourglass-shaped dispersion remain at K. However, further heating above K induces a broad ridge centered at ; thereby the hourglass-shaped dispersion becomes blurred above the pseudogap temperature. The localized spin nature of magnetic excitations below suggests that the pseudogap is related to a proximity to a Mott insulator rather than being a precursor of Cooper pairs.
脇本 秀一; 池内 和彦*; 新井 正敏; 藤田 全基*; 梶本 亮一; 川村 奨*; 松浦 直人*; 中島 健次; 山田 和芳*
JPS Conference Proceedings (Internet), 8, p.034013_1 - 034013_6, 2015/09
Previous neutron results of LaSrCuO (LSCO) by TOF measurements revealed that magnetic dynamical structure factor has a maximum at 18 meV. To clarify the origin of the maximum, we carried out 4 dimensional mapping of dynamical structure factor to see details of both magnons and phonons. We found that = 0 shows ordinary spin waves while = 0.08 shows a maximum at 18 meV where -independent phonon branch crosses. This imply that in superconducting compositions phonon may also indirectly related to the superconductivity.
富安 啓輔*; 岩佐 和晃*; 植田 浩明*; 新高 誠司*; 高木 英典*; 河村 聖子; 菊地 龍弥; 稲村 泰弘; 中島 健次; 山田 和芳*
Physical Review Letters, 113(23), p.236402_1 - 236402_5, 2014/12
佐藤 研太朗*; 松浦 直人*; 藤田 全基*; 梶本 亮一; Ji, S.*; 池内 和彦*; 中村 充孝; 稲村 泰弘; 新井 正敏; 榎木 勝徳*; et al.
JPS Conference Proceedings (Internet), 3, p.017010_1 - 017010_6, 2014/06
We studied the temperature dependence of spin excitation in the underdoped LaSrCuO in a wide energy range. At low temperature, a clear magnetic signal emerging from incommensurate (IC) (0.50.09, 0.5) positions was observed. The low-energy (10 meV) IC signal was confirmed at 200K, while the IC signal gradually merges upon warming and turns into a single commensurate peak centered at (0.5, 0.5) at 300 K. The overall spectral shape above 60 meV measured at 5 K and 350 K was almost the same, meaning the weak thermal effect on the high-energy dispersion relation. This weak change in the high-energy dispersion is consistent with the localized spin picture, whereas the robust IC structure against the temperature would be difficult to explain within a simple stripe model.
岡本 淳*; 中尾 裕則*; 山崎 裕一*; 和達 大樹*; 田中 新*; 久保田 正人; 堀金 和正*; 村上 洋一*; 山田 和芳*
Journal of the Physical Society of Japan, 83(4), p.044705_1 - 044705_6, 2014/04
The antiferromagnetic insulator LaCaCoO has been investigated by Co L-edge and O K-edge X-rayabsorption spectroscopy (XAS) measurements and Co L-edge resonant soft X-ray magnetic scattering (RXMS)measurement to determine the Co electronic structures associated with magnetic ordering. Co L-edge linear-dichroicXAS shows that Co takes a high-spin (HS) state and Co takes a low-spin (LS) state. Using Co L-edge RXMS, wedirectly determined that an antiferromagnetic order is formed with a HS state of Co ions. Moreover, the spin andorbital angular momenta of the Co HS state are quantitatively estimated to be 1.10.1 and 1.00.1, respectively,and to align parallel in the ab plane by utilizing the cluster model calculation. The large orbital angular momentum of the Co HS state originates from the small -symmetry crystal field splitting of levels, which is comparable with the spin-orbit coupling constant of the Co 3 orbital.
石井 賢司; 藤田 全基*; 佐々木 隆了*; Minola, M.*; Dellea, G.*; Mazzoli, C.*; Kummer, K.*; Ghiringhelli, G.*; Braicovich, L.*; 遠山 貴己*; et al.
Nature Communications (Internet), 5, p.3714_1 - 3714_8, 2014/04
We combine X-ray and neutron inelastic scattering measurements to track the doping dependence of both spin and charge excitations in electron-doped materials. Copper resonant inelastic X-ray scattering spectra show that magnetic excitations shift to higher energy upon doping. Their dispersion becomes steeper near the magnetic zone center and they deeply mix with charge excitations, indicating that electrons acquire a highly itinerant character in the doped metallic state. Moreover, above the magnetic excitations, an additional dispersing feature is observed near the -point, and we ascribe it to particle-hole charge excitations. These properties are in stark contrast with the more localized spin-excitations (paramagnons) recently observed in hole-doped compounds even at high doping-levels.
Park, S. R.*; 福田 竜生; Hamann, A.*; Lamago, D*; Pintschovius, L.*; 藤田 全基*; 山田 和芳*; Reznik, D.*
Physical Review B, 89(2), p.020506_1 - 020506_5, 2014/01
In superconducting copper oxides, some Cu-O bond-stretching phonons around 70 meV show anomalous giant softening and broadening of electronic origin, and electronic dispersions have large renormalization kinks near the same energy. These observations suggest that phonon broadening originates from quasiparticle excitations across the Fermi surface and the electronic dispersion kinks originate from coupling to anomalous phonons. We measured the phonon anomaly in underdoped ( = 0.05) and overdoped ( = 0.20 and 0.25) LaSrCuO by inelastic neutron and X-ray scattering with high resolution. Combining these and previously published data, we found that doping dependence of the magnitude of the giant phonon anomaly is very different from that of the ARPES kink, i.e., the two phenomena are not connected. We show that these results provide indirect evidence that the phonon anomaly originates from novel collective charge excitations as opposed to interactions with electron-hole pairs. Their amplitude follows the superconducting dome so these charge modes may be important for superconductivity.
田中 亮太*; 石原 量*; 三好 和義*; 梅野 太輔*; 斎藤 恭一*; 浅井 志保; 山田 伸介*; 廣田 英幸*
Separation Science and Technology, 49(1), p.154 - 159, 2014/01
Extractants impregnated onto porous materials exhibit high performance in adsorption kinetics of metal ions because metal ions are transported by the permeative flow of a metal solution through pores. A simple scheme for the stable impregnation of extractants is necessary to extend the application of extractants. Aliquat 336 was impregnated onto a porous sheet on the basis of the hydrophobic and electrostatic interactions between the octyl group of Aliquat 336 and the undecanoicacid-group-containing polymer chain grafted onto the porous sheet. Palladium chloride solution was fed to the bed charged with the Aliquat 336-impregnated porous sheet, driven by a pressure difference. The dynamic binding capacity of the Aliquat 336-impregnated porous sheet was 0.60 mmol/g, which was one or two orders of magnitude higher than the space velocities of conventional Aliquat 336-impregnated beads.
脇本 秀一; 石井 賢司; 木村 宏之*; 池内 和彦*; 吉田 雅洋*; 足立 匡*; Casa, D.*; 藤田 全基*; 福永 靖*; Gog, T.*; et al.
Physical Review B, 87(10), p.104511_1 - 104511_7, 2013/03
We have performed resonant inelastic X-ray scattering (RIXS) near the Cu- edge on various cuprate superconductors, covering underdoped to heavily overdoped regimes and focusing on charge excitations inside the charge-transfer gap. RIXS measurements with = 9.003 keV on metallic LaSrCuO and BiPbSrCuO exhibit a dispersive intraband excitation below 4 eV, similar to that observed in the electron-doped NdCeCuO. This is the first observation of a dispersive intraband excitation in a hole-doped system, evidencing that both electron- and hole-doped systems have a similar dynamical charge correlation function.
和田 剛*; 石原 量*; 三好 和義*; 梅野 太輔*; 斎藤 恭一*; 浅井 志保; 山田 伸介*; 廣田 英幸*
Solvent Extraction and Ion Exchange, 31(2), p.210 - 220, 2013/02
松浦 直人*; 藤田 全基*; 平賀 晴弘*; 古府 麻衣子*; 木村 宏之*; 脇本 秀一; Perring, T. G.*; Frost, C. D.*; 山田 和芳*
Physical Review B, 86(13), p.134529_1 - 134529_8, 2012/10
Systematic inelastic neutron scattering studies have been performed on LaSrCuNiO in order to elucidate the microscopic mechanism of magnetic Ni impurity doping effects on spin dynamics and superconductivity. In contrast to Zn doping, which precipitates static or quasistatic spin correlations around dopant, Ni doping remarkably reduces , the minimum energy of the upward branch of the hourglass-shaped magnetic dispersion where a commensurate magnetic peak is observed. Ni doping at further reduces to zero energy and broadens the distribution of , corresponding to the appearance of the normal state at base temperature ( K) as well as the broadening of the superconducting transition.
石井 賢司; 筒井 健二; 池内 和彦*; Jarrige, I.; 水木 純一郎; 平賀 晴弘*; 山田 和芳*; 遠山 貴己*; 前川 禎通; 遠藤 康夫*; et al.
Physical Review B, 85(10), p.104509_1 - 104509_5, 2012/03
We perform a resonant inelastic X-ray scattering (RIXS) study of Ni-substituted LaCuO and Cu-substituted LaNiO.Resonantly enhanced charge-transfer excitations are successfully observed by tuning the incident photon energy to the -edge of the substituted element. These excitations display a very weak momentum dependence, evidencing their local character. We find a shift in the energy of the onset edge of these features compared with the non-substituted compounds LaCuO and LaNiO. This shift is quantitatively reproduced by exact diagonalization calculations of the RIXS spectra. RIXS is shown to be a powerful tool to probe the electronic states of substituted elements and to understand their interaction with surrounding atoms.
石原 量*; 浅井 志保; 乙坂 重嘉; 山田 伸介*; 廣田 英幸*; 三好 和義*; 梅野 太輔*; 斎藤 恭一*
Solvent Extraction and Ion Exchange, 30(2), p.171 - 180, 2012/02
Permeative flow through pores of porous membranes enhances the mass transfer of target ions. When polymer chains containing functional groups are appended to the pore surface of porous membranes, a high-speed collection of target ions is achieved. In this study, an octadecylamino-group-introduced polymer chain grafted onto a porous sheet was impregnated with bis(2-ethylhexyl)phosphate (HDEHP). The porous sheet into which a CHNH group was introduced was immersed in HDEHP/ethanol solution. The liquid permeability of a cartridge charged with the HDEHP-impregnated porous sheet in disk form was 96% that of the starting-porous-disk-packed cartridge. The equilibrium binding capacity was 0.32 mol per kg of the disk. The HDEHP-impregnated porous sheet was found to be applicable to the preconcentration of trace amounts of lanthanides prior to their measurement by ICP-MS.
鬼柳 善明*; 木野 幸一*; 古坂 道弘*; 平賀 富士夫*; 加美山 隆*; 加藤 幾芳*; 井頭 政之*; 片渕 竜也*; 水本 元治*; 大島 真澄; et al.
Journal of the Korean Physical Society, 59(2), p.1781 - 1784, 2011/08
吉良 弘; 坂口 佳史; 奥 隆之; 鈴木 淳市; 中村 充孝; 新井 正敏; 遠藤 康夫; Chang, L.-J.; 加倉井 和久; 有本 靖*; et al.
Journal of Physics; Conference Series, 294, p.012014_1 - 012014_5, 2011/06
The pulsed neutron source of J-PARC has started to operate in 2008 in Japan. To study structure of magnetic material and soft matters, polarized neutron scattering techniques are very important and powerful tools. It is urgently necessary for us to develop neutron spin polarizers for pulsed neutron scattering experiments. So we began the development of the in-situ SEOP system aiming to use it as a NSF for incident beam polarization and polarization analysis. In previous test performed by Ino et al., the He polarization reached 50% and not saturated yet. After that experiment, we began improving the SEOP system by installing the high power laser diode, the prism beam splitter and optimizing the beam-transform optics. By using this improved system, we performed the polarization test at BL10 in J-PRC and achieved the He polarization of 73%. We keep improving this in-situ SEOP system aiming to use it s an incident neutron polarizer at J-PARC.
坂口 佳史; 吉良 弘; 奥 隆之; 篠原 武尚; 鈴木 淳市; 酒井 健二; 中村 充孝; 相澤 一也; 新井 正敏; 能田 洋平; et al.
Journal of Physics; Conference Series, 294(1), p.012017_1 - 012017_7, 2011/06
A polarized He neutron spin filter has been applied to polarization analysis on the small-angle neutron scattering spectrometer SANS-J-II at JRR-3. Measurements were taken on silver behenate, which has several coherent peaks in the small-angle region with a background of spin incoherent hydrogen scattering. Here we demonstrate that the coherent and spin incoherent scattering were successfully separated by the polarization analysis using the He spin filter on the instrument.
坂口 佳史; 吉良 弘; 奥 隆之; 篠原 武尚; 鈴木 淳市; 酒井 健二; 中村 充孝; 鈴谷 賢太郎; 相澤 一也; 新井 正敏; et al.
Journal of Physics; Conference Series, 294(1), p.012004_1 - 012004_7, 2011/06
In spin-exchange optical pumping, there is unknown excess relaxation, called the X-factor, that limits attainable He polarization. It is known that the X-factor depends on the glass containers. Hence, it is expected that there are cell-to-cell variations in microscopic structure among the cells and that these variations affect the attainable He polarization. However, microscopic structure of the glasses for He neutron spin filters has not been clarified yet. In this paper, we have performed precise X-ray diffraction measurements for the glasses at SPring-8 using synchrotron radiation. The structural differences are observed between several types of glasses, and also, between the GE180 glass pieces with different thermal treatment. Based on the results, the structural influence on the performance of He neutron spin filters is discussed.
吉良 弘; 坂口 佳史; 奥 隆之; 鈴木 淳市; 中村 充孝; 新井 正敏; 加倉井 和久; 遠藤 康夫; 有本 靖*; 猪野 隆*; et al.
Physica B; Condensed Matter, 406(12), p.2433 - 2435, 2011/06
Polarized neutron scattering techniques are very important and powerful tools to study the fundamental structures of magnetic materials and soft matters. He has a very large absorption cross section for only neutrons in opposite spin state to that of the He nucleus. The scattering cross section of He is small. These two features allow nuclear spin polarized He gas to work as a NSF. Compared with other spin filters such as Heusler alloys and magnetic supermirrors, the He gas NSF have following advantages: it can polarize various energy of neutron such as cold, thermal and hot neutrons, it can work for broadband neutrons and it can be used for wide area and large divergence neutron beams. These characteristics of polarized He are convenient in use with J-PARC as NSF. We began the development of the on beam SEOP system aiming to use it s a NSF for incident beam polarisation and polarisation analysis. In this paper, we report the current development of SEOP system in Japan.
坂口 佳史; 吉良 弘; 奥 隆之; 篠原 武尚; 鈴木 淳市; 酒井 健二; 中村 充孝; 鈴谷 賢太郎; 相澤 一也; 新井 正敏; et al.
Physica B; Condensed Matter, 406(12), p.2443 - 2447, 2011/06
Polarized He neutron spin filters have attracted much attention because of their available wide energy range for polarizing neutrons and their large solid-angle. To use He neutron spin filters for the experiments, it is necessary to produce glass cells with good quality. For this purpose, we made research on the glass cells from several aspects. Firstly, we investigated on the microscopic structure for several glasses by means of X-ray diffraction measurement and tried to find a good measure of evaluating the quality of the cells in terms of their structure. Secondly, we investigated on the glass window, which the laser beam passes through for optical pumping. Thirdly, the cells should be optimized for the polarized neutron scattering experiments and the background from the cells needs to be evaluated. The scattered intensity from the cell in small-angle neutron scattering will also be presented.