1,359 results on '"Yoshizawa, H."'
Search Results
2. Pauli-limited superconductivity and antiferromagnetism in the heavy-fermion compound CeCo(In1-xZnx)5
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Yokoyama, M., Mashiko, H., Otaka, R., Sakon, Y., Fujimura, K., Tenya, K., Kondo, A., Kindo, K., Ikeda, Y., Yoshizawa, H., Shimizu, Y., Kono, Y., and Sakakibara, T.
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Condensed Matter - Strongly Correlated Electrons ,Condensed Matter - Superconductivity - Abstract
We report on the anisotropic properties of Pauli-limited superconductivity (SC) and antiferromagnetism (AFM) in the solid solutions CeCo(In_{1-x}Zn_x)_5 (x<=0.07). In CeCo(In_{1-x}Zn_x)_5, the SC transition temperature T_c is continuously reduced from 2.3 K (x=0) to ~1.4 K (x=0.07) by doping Zn, and then the AFM order with the transition temperature of T_N~2.2 K develops for x larger than ~0.05. The present thermal, transport and magnetic measurements under magnetic field B reveal that the substitution of Zn for In yields little change of low-temperature upper critical field \mu_0H_{c2} for both the tetragonal a and c axes, while it monotonically reduces the SC transition temperature T_c. In particular, the magnitudes of \mu_0H_{c2} at the nominal Zn concentration of x = 0.05 (measured Zn amount of ~0.019) are 11.8 T for B||a and 4.8 T for B||c, which are as large as those of pure compound though T_c is reduced to 80% of that for x=0. We consider that this feature originates from a combination of both an enhanced AFM correlation and a reduced SC condensation energy in these alloys. It is also clarified that the AFM order differently responds to the magnetic field, depending on the field directions. For B||c, the clear anomaly due to the AFM transition is observed up to the AFM critical field of ~5 T in the thermodynamic quantities, whereas it is rapidly damped with increasing B for B||a. We discuss this anisotropic response on the basis of a rich variety of the AFM modulations involved in the Ce115 compounds., Comment: 10 pages, 7 figures
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- 2015
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3. Pharmacological Actions of Indoxyl Sulfate and AST-120 That Should Be Recognized for the Strategic Treatment of Patients with Chronic Kidney Disease
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Nagata D and Yoshizawa H
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chronic kidney disease (ckd) ,uremic toxin ,indoxyl sulfate (is) ,ast-120 ,hemodialysis ,medication adherence ,Diseases of the genitourinary system. Urology ,RC870-923 - Abstract
Daisuke Nagata, Hiromichi Yoshizawa Division of Nephrology, Department of Internal Medicine, Jichi Medical University, Tochigi, JapanCorrespondence: Daisuke Nagata Tel +81 285 58 7346Fax +81 285 44 4869Email nagatad@jichi.ac.jpAbstract: Although there are many uremic substances in the body, the most studied and well-known molecule that predominantly binds to plasma proteins is indoxyl sulfate (IS). Many research groups have reported IS to have toxic effects on the kidney and cardiovascular system. It is difficult to remove IS with regular hemodialysis or hemodiafiltration. On the other hand, AST-120 has the capacity to bind to indole, which is a precursor of IS in the intestinal tract and excrete it in feces. IS production in the liver is efficiently suppressed by AST-120 administration. However, large-scale clinical studies have not shown that AST-120 suppresses hard endpoints such as doubling serum creatinine, end-stage renal disease, and death. In patients with accelerated chronic kidney disease (CKD) progression, AST-120 is expected to suppress those hard renal endpoints, but only when compliance to treatment is high. It is necessary to validate the renal protective effect of AST-120, as expected from the basic study on IS, including more patients with slowly progressive CKD in a large-scale clinical study in the future.Keywords: chronic kidney disease, CKD, uremic toxin, indoxyl sulfate, IS, AST-120, hemodialysis, medication adherence
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- 2020
4. Structural and magnetic properties in the quantum S=1/2 dimer systems Ba3(Cr1-xVx)2O8 with site disorder
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Hong, Tao, Zhu, L. Y., Ke, X., Garlea, V. O., Qiu, Y., Nambu, Y., Yoshizawa, H., Zhu, M., Granroth, G. E., Savici, A. T., Gai, Zheng, and Zhou, H. D.
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Condensed Matter - Materials Science ,Condensed Matter - Strongly Correlated Electrons - Abstract
We report a comprehensive study of dc susceptibility, specific heat, neutron diffraction, and inelastic neutron scattering measurements on polycrystalline Ba3(Cr1-xVx)2O8 samples, where x=0, 0.06, 0.15, and 0.53. A Jahn-Teller structure transition occurs for x=0, 0.06, and 0.15 samples and the transition temperature is reduced upon vanadium substitution from 70(2) K at x=0 to 60(2) K at x=0.06 and 0.15. The structure becomes less distorted as x increases and such transition disappears at x=0.53. The observed magnetic excitation spectrum indicates that the singlet ground state remains unaltered and spin gap energy \Delta=1.3(1) meV is identical within the instrument resolution for all x. In addition, the dispersion bandwidth W decreases with increase of x. At x=0.53, W is reduced to 1.4(1) meV from 2.0(1) meV at x=0., Comment: 11 pages, 7 figures, some typos are corrected
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- 2013
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5. Long-range order and spin-liquid states of polycrystalline Tb$_{2+x}$Ti$_{2-x}$O$_{7+y}$
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Taniguchi, T., Kadowaki, H., Takatsu, H., Fåk, B., Ollivier, J., Yamazaki, T., Sato, T. J., Yoshizawa, H., Shimura, Y., Sakakibara, T., Hong, T., Goto, K., Yaraskavitch, L. R., and Kycia, J. B.
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Condensed Matter - Strongly Correlated Electrons ,Condensed Matter - Disordered Systems and Neural Networks - Abstract
Low-temperature states of polycrystalline samples of a frustrated pyrochlore oxide Tb$_{2+x}$Ti$_{2-x}$O$_{7+y}$ have been investigated by specific heat, magnetic susceptibility, and neutron scattering experiments. We have found that this system can be tuned by a minute change of $x$ from a spin-liquid state ($x < x_{\text{c}}$) to a partly ordered state with a small antiferromagnetic ordering of the order of $0.1 \mu_{\text{B}}$. Specific heat shows a sharp peak at a phase transition at $T_{\text{c}}= 0.5$ K for $x=0.005$. Magnetic excitation spectra for this sample change from a quasielastic to a gapped type through $T_{\text{c}}$. The possibility of a Jahn-Teller transition is discussed., Comment: 5 pages, 5 figures; Fig.1 replaced
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- 2012
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6. Short-range Charge and Spin Superstructures in Doped Layered Co Perovskites
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Sakiyama, N., Zaliznyak, I. A., Lee, S. -H., Mitsui, Y., and Yoshizawa, H.
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Condensed Matter - Strongly Correlated Electrons ,Condensed Matter - Materials Science - Abstract
We have investigated cobaltite relatives of the layered perovskite cuprates and nickelates, Pr$_{2-x}$Ca$_x$CoO$_4$ ($0.39 \leq x \leq 0.73$) and La$_{2-x}$Sr$_x$CoO$_4$ ($x = 0.61$), using elastic neutron scattering. We have discovered doping-dependent incommensurate short-range ordering of charges and magnetic moments, which in cobaltites occur in the range of heavy doping, $ 0.5 \lesssim x \lesssim 0.75$. The charge order exists already at room temperature and shows no change on cooling. The incommensurability of its propagation vector, ${\bf Q}_c = (\epsilon_c,0,l)$, roughly scales with the concentration of Co$^{2+}$ ions, $\epsilon_c \sim (1-x)$. Magnetic order is only established at low T$\lesssim 40$ K and has twice larger periodicity, indicating a dominant antiferromagnetic correlation between the nearest Co$^{2+}$ spins., Comment: 4 pages 4 figures
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- 2008
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7. Analytical/Experimental Study on Composite Behavior in Strengthening Structures with Bonded Carbon Fiber Sheets
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Wu, Z., primary and Yoshizawa, H., additional
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- 2019
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8. Low-lying optical phonon modes in the filled skutterudite CeRu4Sb12
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Lee, C. H., Hase, I., Sugawara, H., Yoshizawa, H., and Sato, H.
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Condensed Matter - Strongly Correlated Electrons - Abstract
The phonon dynamics of filled skutterudite CeRu4Sb12 have been studied at room temperature by inelastic neutron scattering. Optical phonons associated with a large vibration of Ce atoms are observed at a relatively low energy of E = 6 meV, and show anticrossing behavior with acoustic phonons. We propose that the origin of the low lattice thermal conductivity in filled skutterudites can be attributed to intensive Umklapp scattering originating from low-lying optical phonons. By an analysis based on a Born-von Karman force model, the longitudinal force constants of the nearest Ce-Sb and Ce-Ru pairs are estimated to be 0.025 mdyn/A, while that of the nearest Ru-Sb pair is estimated to be 1.4 mdyn/A, indicating that the Ce atoms are bound very weakly to the surrounding rigid RuSb6-octahedron cages., Comment: 4pages, 5 figures, J. Phys. Soc. Jpn. (2006) in press
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- 2006
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9. Pressure-temperature phase diagram of the heavy-electron superconductor URu2Si2
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Amitsuka, H., Matsuda, K., Kawasaki, I., Tenya, K., Yokoyama, M., Sekine, C., Tateiwa, N., Kobayashi, T. C., Kawarazaki, S., and Yoshizawa, H.
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Condensed Matter - Strongly Correlated Electrons ,Condensed Matter - Superconductivity - Abstract
The pressure-temperature phase diagram of the heavy-electron superconductor URu2Si2 has been reinvestigated by ac-susceptibility and elastic neutron-scattering (NS) measurements performed on a small single-crystalline rod (2 mm in diameter, 6 mm in length) in a Cu-Be clamp-type high-pressure cell (P < 1.1 GPa). At ambient pressure, this sample shows the weakest antiferromagnetic (AF) Bragg reflections reported so far, corresponding to the volume-averaged staggered moment of mord ~ 0.011 mB/U. Under applied pressure, the AF scattering intensity exhibits a sharp increase at P ~ 0.7 GPa at low temperatures. The saturation value of the AF scattering intensity above 0.7 GPa corresponds to mord ~ 0.41 mB/U, which is in good agreement with that (~ 0.39 mB/U) observed above 1.5 GPa in our previous NS measurements. The superconductivity is dramatically suppressed by the evolution of AF phase, indicating that the superconducting state coexists only with the hidden order phase. The presence of parasitic ferro- and/or antiferromagnetic phases with transition temperatures T1star =120(5) K, T2star = 36(3) K and T3star = 16.5(5) K and their relationship to the low-T ordered phases are also discussed., Comment: 6 pages, 7 figures, submitted to J. Magn. Magn. Mater. (ICM2006)
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- 2006
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10. New Magnetic State in Incommensurate Magnetic Phase of Heavy-Fermion Superconductor CeRh0.6Co0.4In5
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Yokoyama, M., Amitsuka, H., Matsuda, K., Gawase, A., Oyama, N., Kawasaki, I., Tenya, K., and Yoshizawa, H.
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Condensed Matter - Strongly Correlated Electrons - Abstract
We performed elastic neutron scattering experiments on solid solution CeRh1-xCoxIn5 with x=0.4 to clarify the nature of the antiferromagnetic (AF) phase in the vicinity of the quantum critical point. We observed the incommensurate AF order below T_Nh=3.5 K. The structure of the incommensurate AF order is basically unchanged from that for pure CeRhIn5. We further found the evolution of a new commensurate AF order with the modulation of q_c=(1/2,1/2,1/2) below T_Nc=2.9 K. The volume-averaged moments for the incommensurate and commensurate AF phases are 0.38 mu_B/Ce and 0.21 mu_B/Ce, respectively, which are reduced from the incommensurate AF moment (0.75 mu_B/Ce) for pure CeRhIn5. We suggest from these results that the commensurate magnetic correlation may be tightly coupled with the superconductivity observed below T_c=1.4 K., Comment: 5 pages, 4 figures, to appear in J. Phys. Soc. Jpn
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- 2006
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11. Electronically smectic-like phase in a nearly half-doped manganite
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Ye, F., Fernandez-Baca, J. A., Dai, Pengcheng, Lynn, J. W., Kawano-Furukawa, H., Yoshizawa, H., Tomioka, Y., and Tokura, Y.
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Condensed Matter - Strongly Correlated Electrons - Abstract
We use neutron scattering to study the spin and charge/orbital ordering (CO-OO) in the nearly half-doped perovskite manganite $Pr_{0.55}(Ca_{0.8}Sr_{0.2})_{0.45}MnO_3$ (PCSMO). On cooling from room temperature, PCSMO first enters into a CO-OO state below $T_{CO}$ and then becomes a CE-type long-range ordered antiferromagnet below $T_N$. At temperatures above $T_N$ but below $T_{CO}$ ($T_N
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- 2005
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12. Observation of Modulated Quadrupolar Structures in PrPb3
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Onimaru, T., Sakakibara, T., Aso, N., Yoshizawa, H., Suzuki, H. S., and Takeuchi, T.
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Condensed Matter - Strongly Correlated Electrons ,Condensed Matter - Materials Science - Abstract
Neutron diffraction measurements have been performed on the cubic compound PrPb3 in a [001] magnetic field to examine the quadrupolar ordering. Antiferromagnetic components with q=(1/2+-d 1/2 0), (1/2 1/2+-d 0) (d~1/8) are observed below the transition temperature TQ (0.4 K at H=0) whose amplitudes vary linear with H and vanish at zero field, providing the first evidence for a modulated quadrupolar phase. For H<1 T, a non-square modulated state persists even below 100 mK suggesting quadrupole moments associated with a Gamma3 doublet ground state to be partially quenched by hybridization with conduction electrons., Comment: Physical Review Letters, in press. 4 pages, 4 figures
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- 2005
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13. Magnetic Excitations in U(Ru_{1-x}Rh_x)_2Si_2 (x<=0.03)
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Yokoyama, M., Amitsuka, H., Itoh, S., Kawasaki, I., Tenya, K., and Yoshizawa, H.
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Condensed Matter - Strongly Correlated Electrons - Abstract
We have investigated magnetic excitations for a mixed phase of hidden order (HO) and the antiferromagnetic (AF) order in U(Ru_{1-x}Rh_x)_2Si_2 (x <= 0.03) by means of inelastic neutron scattering. The inelastic peaks observed at Q=(1,0,0) and (1,0.4,0) in the HO phase for x=0 and 0.015 at 1.4 K are found to be strongly reduced in the AF dominant compositions of x=0.02 and 0.03. Similar behavior is observed as the HO is replaced by the AF order upon cooling for x=0.02. The x-T region in which the strong reduction of inelastic peaks is observed corresponds to the AF-rich region, indicating that the magnetic excitations typical for the HO-phase vanish in the AF phase., Comment: 2 pages, 2 figures, to appear in the proceedings of SCES2004
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- 2004
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14. A-site Randomness Effect on Structural and Physical Properties of Ba-based Perovskite Manganites
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Nakajima, T., Yoshizawa, H., and Ueda, Y.
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Condensed Matter - Strongly Correlated Electrons ,Condensed Matter - Materials Science - Abstract
The discovery of novel structural and physical properties in the $A$-site ordered manganite $R$BaMn$_{2}$O$_{6}$ ($R$ = Y and rare earth elements) has demanded new comprehension about perovskite manganese oxides. In the present study, the $A$-site disordered form, $R_{0.5}$Ba$_{0.5}$MnO$_{3}$, has been investigated and compared with both $R$BaMn$_{2}$O$_{6}$ and $R_{0.5}A_{0.5}$MnO$_{3}$ ($A$: Sr, Ca) in the structures and electromagnetic properties. $R_{0.5}$Ba$_{0.5}$MnO$_{3}$ has a primitive cubic perovskite cell in the structure and magnetic glassy states are dominant as its ground state, in contrast to the ordinary disordered $R_{0.5}A_{0.5}$MnO$_{3}$ ($A$: Sr, Ca). In Pr-compounds with various degrees of Pr/Ba randomness at the $A$-sites, the $A$-site disorder gradually suppresses both ferromagnetic and A-type antiferromagnetic transitions and finally leads to a magnetic glassy state in Pr$_{0.5}$Ba$_{0.5}$MnO$_{3}$. A peculiar behavior, multi-step magnetization and resistivity change, has been observed in Pr$_{0.5}$Ba$_{0.5}$MnO$_{3}$. These properties could be closely related to any spatial heterogeneity caused by the random distribution of Ba$^{2 +}$ and $R^{3 +}$ with much different ionic radius., Comment: 9 pages, to be published in J. Phys. Soc. Jpn. 73 Aug. (2004)
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- 2004
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15. Neutron diffraction study of TbMnO3: Magnetic structure revisited
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Kajimoto, R., Yoshizawa, H., Shintani, H., Kimura, T., and Tokura, Y.
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Condensed Matter - Strongly Correlated Electrons - Abstract
Magnetic ordering in TbMnO3 was revisited by a neutron diffraction study. In addition to the previously reported A-type and G-type modulated structures with a propagation vector (0,q_Mn,0), we found C-type and F-type orderings of the Mn moments. All the components appear below T_N^Mn = 46 K, and the G, C,and F-type components are enhanced below T_lock = 28 K, where q_Mn ordering locks at its low temperature value. The locking of the propagation vector also yields the squaring up of the spin arrangement. The magnetic moments of Tb ions show a quasi long-range ordering below T_N^Tb = 7 K. It drastically promotes the development of the G, C, and F-type components while suppressing the A-type components., Comment: 5 pages, 4 figures
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- 2004
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16. Competition between hidden order and antiferromagnetism in URu_2Si_2 under uniaxial stress studied by neutron scattering
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Yokoyama, M., Amitsuka, H., Tenya, K., Watanabe, K., Kawarazaki, S., Yoshizawa, H., and Mydosh, J. A.
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Condensed Matter - Strongly Correlated Electrons - Abstract
We have performed elastic neutron scattering experiments under uniaxial stress sigma applied along the tetragonal [100], [110] and [001] directions for the heavy electron compound URu2Si2. We found that antiferromagnetic (AF) order with large moment is developed with sigma along the [100] and [110] directions. If the order is assumed to be homogeneous, the staggered ordered moment mu_o continuously increases from 0.02 mu_B (sigma=0) to 0.22 mu_B (0.25 GPa). The rate of increase partial mu_o/partial sigma is ~ 1.0 mu_B/GPa, which is four times larger than that for the hydrostatic pressure (partial mu_o/partial P sim 0.25 mu_B/GPa). Above 0.25 GPa, mu_o shows a tendency to saturate, similar to the hydrostatic pressure behavior. For sigma||[001], mu_o shows only a slight increase to 0.028 mu_B (sigma = 0.46 GPa) with a rate of ~ 0.02 mu_B/GPa, indicating that the development of the AF state highly depends on the direction of sigma. We have also found a clear hysteresis loop in the isothermal mu_o(sigma) curve obtained for sigma||[110] under the zero-stress-cooled condition at 1.4 K. This strongly suggests that the sigma-induced AF phase is metastable, and separated from the "hidden order" phase by a first-order phase transition. We discuss these experimental results on the basis of crystalline strain effects and elastic energy calculations, and show that the c/a ratio plays a key role in the competition between these two phases., Comment: 9 pages, 7 figures, to appear in Physical Review B
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- 2003
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17. Neutron Scattering Study on Competition between Hidden Order and Antiferromagnetism in U(Ru_{1-x}Rh_x)_2Si_2 (x <= 0.05)
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Yokoyama, M., Amitsuka, H., Itoh, S., Kawasaki, I., Tenya, K., and Yoshizawa, H.
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Condensed Matter - Strongly Correlated Electrons - Abstract
We have performed elastic and inelastic neutron scattering experiments on the solid solutions U(Ru_{1-x}Rh_x)_2Si_2 for the Ru rich concentrations: x=0, 0.01, 0.02, 0.025, 0.03, 0.04 and 0.05. Hidden order is suppressed with increasing x, and correspondingly the onset temperature T_m (~ 17.5 K at x=0) of weak antiferromagnetic (AF) Bragg reflection decreases. For x=0.04 and 0.05, no magnetic order is detected in the investigated temperature range down to 1.4 K. In the middle range, 0.02 <= x <= 0.03, we found that the AF Bragg reflection is strongly enhanced. At x=0.02, this takes place at ~ 7.7 K (=T_M), which is significantly lower than T_m (~ 13.7 K). T_M increases with increasing x, and seems to merge with T_m at x=0.03. If the AF state is assumed to be homogeneous, the staggered moment \mu_o estimated at 1.4 K increases from 0.02(2) \mu_B/U (x=0) to 0.24(1) \mu_B/U (x=0.02). The behavior is similar to that observed under hydrostatic pressure (\mu_o increases to ~ 0.25 \mu_B/U at 1.0 GPa), suggesting that the AF evolution induced by Rh doping is due to an increase in the AF volume fraction. We also found that the magnetic excitation observed at Q=(1,0,0) below T_m disappears as T is lowered below T_M., Comment: 4 pages, 4 figures, submitted to J. Phys. Soc. Jpn
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- 2003
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18. Anisotropy in the Antiferromagnetic Spin Fluctuations of Sr2RuO4
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Nagata, T., Urata, M., Kawano-Furukawa, H., Yoshizawa, H., Kadowaki, H., and Dai, P.
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Condensed Matter - Strongly Correlated Electrons - Abstract
It has been proposed that Sr_2RuO_4 exhibits spin triplet superconductivity mediated by ferromagnetic fluctuations. So far neutron scattering experiments have failed to detect any clear evidence of ferromagnetic spin fluctuations but, instead, this type of experiments has been successful in confirming the existence of incommensurate spin fluctuations near q=(1/3 1/3 0). For this reason there have been many efforts to associate the contributions of such incommensurate fluctuations to the mechanism of its superconductivity. Our unpolarized inelastic neutron scattering measurements revealed that these incommensurate spin fluctuations possess c-axis anisotropy with an anisotropic factor \chi''_{c}/\chi''_{a,b} of \sim 2.8. This result is consistent with some theoretical ideas that the incommensurate spin fluctuations with a c-axis anisotropy can be a origin of p-wave superconductivity of this material., Comment: 5 pages, 3 figures; accepted for publication in PRB
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- 2003
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19. Ferromagnetic insulating phase in Pr{1-x}Ca{x}MnO3
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Kajimoto, R., Mochizuki, H., Yoshizawa, H., Okamoto, S., and Ishihara, S.
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Condensed Matter - Strongly Correlated Electrons - Abstract
A ferromagnetic insulating (FM-I) state in Pr0.75Ca0.25MnO3 has been studied by neutron scattering experiment and theoretical calculation. The insulating behavior is robust against an external magnetic field, and is ascribed to neither the phase separation between a ferromagnetic metallic (FM-M) phase and a non-ferromagnetic insulating one, nor the charge ordering. We found that the Jahn-Teller type lattice distortion is much weaker than PrMnO3 and the magnetic interaction is almost isotropic. These features resembles the ferromagnetic metallic state of manganites, but the spin exchange interaction J is much reduced compared to the FM-M state. The theoretical calculation based on the staggered type orbital order well reproduces several features of the spin and orbital state in the FM-I phase., Comment: REVTeX4, 10 pages, 9 figures
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- 2003
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20. New Stacking Variations of the CE-type Structure in the Metal-Ordered Manganite YBaMn2O6
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Kageyama, H., Nakajima, T., Ichihara, M., Ueda, Y., Yoshizawa, H., and Ohoyama, K.
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Condensed Matter - Strongly Correlated Electrons - Abstract
For the paramagnetic insulating phase in the metal-ordered manganite YBaMn2O6, the so-called CE-type of charge/orbital ordered state was observed within the monoclinic ab-plane, which is most commonly observed for the ordinary half doped manganites. However, TEM revealed a 4-fold periodicity along the c-axis, suggesting a new stacking pattern, where planes of the CE-type are built up according to the sequence [aabb...]. Interestingly, when th system enters into the antiferromagnetic state, this stacking pattern changes into [aaaa...] or [abab], suggesting close interplay between spins and orbitals. These features are discusses in terms of inherent structural alternation, i.e., the Y/Ba order along the c-axis., Comment: 13 pages, figures included, submitted to Journal of the Physical Society of Japan
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- 2002
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21. Nonequilibrium Antiferromagnetic State in the Heavy Electron Compound URu_2Si_2
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Yokoyama, M., Nozaki, J., Amitsuka, H., Watanabe, K., Kawarazaki, S., Yoshizawa, H., and Mydosh, J. A.
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Condensed Matter - Strongly Correlated Electrons - Abstract
We have investigated the nature of the antiferromagnetic (AF) phase induced by uniaxial stress sigma in URu2Si2, by performing elastic neutron scattering measurements up to 0.4 GPa. We have found that the AF Bragg-peak intensity shows a clear hysteresis loop with sigma under the zero-stress cooling condition. The result strongly suggests that the sigma-induced AF phase is metastable and separated from the coexisting "hidden ordered" phase by a first-order phase transition. We also present the analyses of the crystalline strain effects, and suggest that the c/a ratio plays an important role in the competition between these two phases., Comment: 4 pages, 2 eps figures, To appear in proceedings of SCES 2002 (Krakow)
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- 2002
22. Structures and Electromagnetic Properties of New Metal-Ordered Manganites; RBaMn_{2}O_{6} (R = Y and Rare Earth Elements)
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Nakajima, T., Kageyama, H., Yoshizawa, H., and Ueda, Y.
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Condensed Matter - Strongly Correlated Electrons - Abstract
New metal-ordered manganites RBaMn_{2}O_{6} have been synthesized and investigated in the structures and electromagnetic properties. RBaMn_{2}O_{6} can be classified into three groups from the structural and electromagnetic properties. The first group (R = La, Pr and Nd) has a metallic ferromagnetic transition, followed by an A-type antiferromagnetic transition in PrBaMn_{2}O_{6}. The second group (R = Sm, Eu and Gd) exhibits a charge-order transition, followed by an antiferromagnetic long range ordering. The third group (R = Tb, Dy and Ho) shows successive three phase transitions, the structural, charge/orbital-order and magnetic transitions, as observed in YBaMn_{2}O_{6}. Comparing to the metal-disordered manganites (R^{3+}_{0.5}A^{2+}_{0.5})MnO_{3}, two remarkable features can be recognized in RBaMn_{2}O_{6}; (1) relatively high charge-order transition temperature and (2) the presence of structural transition above the charge-order temperature in the third group. We propose a possible orbital ordering at the structural transition, that is a possible freezing of the orbital, charge and spin degrees of freedom at the independent temperatures in the third group. These features are closely related to the peculiar structure that the MnO_{2} square-lattice is sandwiched by the rock-salt layers of two kinds, RO and BaO with extremely different lattice-sizes., Comment: 5 pages, 4 figures, submitted to J. Phys. Soc. Jpn
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- 2002
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23. Spontaneous rearrangement of the checkerboard charge order to stripe order in La1.5Sr0.5NiO4
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Kajimoto, R., Ishizaka, K., Yoshizawa, H., and Tokura, Y.
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Condensed Matter - Strongly Correlated Electrons - Abstract
The charge ordering in La1.5Sr0.5NiO4 has been studied with neutron diffraction technique. An interesting rearrangement of the charge ordering was observed as a function of temperature. With decreasing temperature, a checkerboard-type charge order is formed below T{CO-C} ~ 480 K. It is, however, taken over by the stripe-type charge order with an incommensurability twice as large as that of the spin order below T{CO-IC} ~ 180 K. Surprisingly, the stripe phase persists up to x = 0.7 for highly hole-doped samples of Nd{2-x}Sr{x}NiO{4} with 0.45 < x < 0.7., Comment: REVTeX4, 5 pages, 5 figures, to be published in Phys. Rev. B
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- 2002
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24. Microscopic spin interactions in the CMR manganites
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Fernandez-Baca, J. A., Dai, Pengcheng, Kawano-Furukawa, H., Yoshizawa, H., Plummer, E. W., Katano, S., Tomioka, Y., and Tokura, Y.
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Condensed Matter - Strongly Correlated Electrons - Abstract
Using inelastic neutron scattering we measured the microscopic magnetic coupling associated with the ferromagnetic (FM) clusters of the ``colossal magnetoresistance'' (CMR) compound Pr$_{0.70}$Ca$_{0.30}$MnO$_3$. When the insulating to metal (I-M) transition is induced by an external magnetic field there is a discontinuous change in the spin-wave stiffness constant. This result indicates that the probed regions undergo a first-order transition from an insulating to a metallic state, and that there are no FM metallic domains in the insulating region. We argue that the I-M transition in the CMR manganites is more complex than the simple percolation of large FM metallic clusters., Comment: 4 pages, 4 figures
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- 2001
25. Novel stripe-type charge ordering in the metallic A-type antiferromagnet Pr{0.5}Sr{0.5}MnO{3}
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Kajimoto, R., Yoshizawa, H., Tomioka, Y., and Tokura, Y.
- Subjects
Condensed Matter - Strongly Correlated Electrons - Abstract
We demonstrate that an A-type antiferromagnetic (AFM) state of Pr{0.5}Sr{0.5}MnO{3} exhibits a novel charge ordering which governs the transport property. This charge ordering is stripe-like, being characterized by a wave vector q ~ (0,0,0.3) with very anisotropic correlation parallel and perpendicular to the stripe direction. This charge ordering is specific to the manganites with relatively wide one-electron band width (W) which often exhibit a metallic A-type AFM state, and should be strictly distinguished from the CE-type checkerboard-like charge ordering which is commonly observed in manganites with narrower W such as La{1-x}Ca{x}MnO{3} and Pr{1-x}Ca{x}MnO{3}., Comment: REVTeX4, 5 pages, 4 figures
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- 2001
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26. Effects of Uniaxial Stress on Antiferromagnetic Moment in the Heavy Electron Compound URu_2Si_2
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Yokoyama, M., Amitsuka, H., Watanabe, K., Kawarazaki, S., Yoshizawa, H., and Mydosh, J. A.
- Subjects
Condensed Matter - Strongly Correlated Electrons - Abstract
We have performed the elastic neutron scattering experiments under uniaxial stress \sigma along the tetragonal [100], [110] and [001] directions for URu2Si2. For \sigma // [100] and [110], the antiferromagnetic moment \mu_o is strongly enhanced from 0.02 \mu_B (\sigma=0) to 0.22 \mu_B (\sigma=2.5 kbar) at 1.5 K. The rate of increase d\mu_o/d\sigma is roughly estimated to be ~ 0.1 \mu_B/kbar, which is much larger than that for the hydrostatic pressure (~ 0.025 \mu_B/kbar). Above 2.5 kbar, \mu_o shows a tendency to saturate similar to the behavior in the hydrostatic pressure. For \sigma // [001], on the other hand, \mu_o shows only a slight increase to 0.028 \mu_B (\sigma = 4.6 kbar) with a rate of ~ 0.002 \mu_B/kbar. The observed anisotropy suggests that the competition between the hidden order and the antiferromagnetic state in URu2Si2 is strongly coupled with the tetragonal four-fold symmetry and the c/a ratio, or both., Comment: 3 pages, 3 eps figures, Proceedings of Int. Conf. on Strongly Correlated Electrons with Orbital Degrees of Freedom (Sendai, Japan, September 11-14, 2001)
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- 2001
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27. Highly Degenerate Canted Spin Structure in Bilayer Manganite La$_{1.1}$Sr$_{1.9}$Mn$_2$O$_7$
- Author
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Kubota, M., Oohara, Y., Yoshizawa, H., Fujioka, H., Hirota, K., Moritomo, Y., and Endoh, Y.
- Subjects
Condensed Matter - Strongly Correlated Electrons - Abstract
We have examined magnetic ordering of the two-dimensional (2D) bilayer manganite La$_{1.1}$Sr$_{1.9}$Mn$_2$O$_7$ with neutron diffraction technique. Due to the two-dimensionality, there appears intense 2D ridge scattering along the tetragonal $(00l)$ direction, and the analyses of such scattering leads to a conclusion that the low temperature spin structure is a canted antiferromagnetic ordering., Comment: 4 pages, 3 figures Email: mkubota@post.kek.jp
- Published
- 2001
28. Spontaneous vortex phase in ErNi2B2C
- Author
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Kawano-Furukawa, H., Habuta, E., Nagata, T., Nagao, M., Yoshizawa, H., Furukawa, N., Takeya, H., and Kadowaki, K.
- Subjects
Condensed Matter - Superconductivity ,Condensed Matter - Strongly Correlated Electrons - Abstract
Below T_{WFM} ~ 2.75K, a weak ferromagnetism and superconductivity coexist in ErNi2B2C. In the present paper, a possibility of a spontaneous vortex phase was examined directly by small angle neutron scattering technique. An external magnetic field was applied to align ferromagnetic domains so that the internal magnetic field induced by the weak ferromagnetism becomes uniform and uniaxial over the bulk sample. When the field is removed, the flux line lattice subsisted below T_{WFM} but disappeared above it. A pinning effect is also discussed. We conclude that the spontaneous vortex state is realized in ErNi2B2C., Comment: 5 pages, 4 figures
- Published
- 2001
29. Ordering Process and Its Hole Concentration Dependence of the Stripe Order in La{2-x}Sr{x}NiO{4}
- Author
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Kajimoto, R., Kakeshita, T., Yoshizawa, H., Tanabe, T., Katsufuji, T., and Tokura, Y.
- Subjects
Condensed Matter - Strongly Correlated Electrons ,Condensed Matter - Superconductivity - Abstract
Ordering process of stripe order in La{2-x}Sr{x}NiO{4} with x being around 1/3 was investigated by neutron diffraction experiments. When the stripe order is formed at high temperature, incommensurability \epsilon of the stripe order has a tendency to show the value close to 1/3 for the samples with x at both sides of 1/3. With decreasing temperature, however, \epsilon becomes close to the value determined by the linear relation of \epsilon = n_h, where n_h is a hole concentration. This variation of the \epsilon strongly affects the character of the stripe order through the change of the carrier densities in stripes and antiferromagnetic domains., Comment: 5 pages, 3 figures, REVTeX, to be published in Phys. Rev. B
- Published
- 2001
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30. Spin dynamical properties and orbital states of the layered perovskite La_2-2x_Sr_1+2x_Mn_2_O_7 (0.3 <= x < 0.5)
- Author
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Hirota, K., Ishihara, S., Fujioka, H., Kubota, M., Yoshizawa, H., Moritomo, Y., Endoh, Y., and Maekawa, S.
- Subjects
Condensed Matter - Strongly Correlated Electrons - Abstract
Low-temperature spin dynamics of the double-layered perovskite La_2-2x_Sr_1+2x_Mn_2_O_7 (LSMO327) was systematically studied in a wide hole concentration range (0.3 <= x < 0.5). The spin-wave dispersion, which is almost perfectly 2D, has two branches due to a coupling between layers within a double-layer. Each branch exhibits a characteristic intensity oscillation along the out-of-plane direction. We found that the in-plane spin stiffness constant and the gap between the two branches strongly depend on x. By fitting to calculated dispersion relations and cross sections assuming Heisenberg models, we have obtained the in-plane (J_para), intra-bilayer (J_perp) and inter-bilayer (J') exchange interactions at each x. At x=0.30, J_para=-4meV and J_perp=-5meV, namely almost isotropic and ferromagnetic. Upon increasing x, J_perp rapidly approaches zero while |J_para| increases slightly, indicating an enhancement of the planar magnetic anisotropy. At x=0.48, J_para reaches -9meV, while J_perp turns to +1meV indicating an antiferromagnetic interaction. Such a drastic change of the exchange interactions can be ascribed to the change of the relative stability of the d_x^2-y^2 and d_3z^2-r^2 orbital states upon doping. However, a simple linear combination of the two states results in an orbital state with an orthorhombic symmetry, which is inconsistent with the tetragonal symmetry of the crystal structure. We thus propose that an ``orbital liquid'' state realizes in LSMO327, where the charge distribution symmetry is kept tetragonal around each Mn site., Comment: 10 pages including 7 figures
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- 2001
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31. Commensurate-Incommensurate transition in the melting process of the orbital ordering in Pr0.5Ca0.5MnO3: neutron diffraction study
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Kajimoto, R., Yoshizawa, H., Tomioka, Y., and Tokura, Y.
- Subjects
Condensed Matter - Strongly Correlated Electrons - Abstract
The melting process of the orbital order in Pr0.5Ca0.5MnO3 single crystal has been studied in detail as a function of temperature by neutron diffraction. It is demonstrated that a commensurate-incommensurate (C-IC) transition of the orbital ordering takes place in a bulk sample, being consistent with the electron diffraction studies. The lattice structure and the transport properties go through drastic changes in the IC orbital ordering phase below the charge/orbital ordering temperature Tco/oo, indicating that the anomalies are intimately related to the partial disordering of the orbital order, unlike the consensus that it is related to the charge disordering process. For the same T range, partial disorder of the orbital ordering turns on the ferromagnetic spin fluctuations which were observed in a previous neutron scattering study., Comment: 5 pages, 2 figures, REVTeX, to be published in Phys. Rev. B
- Published
- 2000
- Full Text
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32. Orbital-ordering-induced anomalous softening of the ferromagnetic spin waves in perovskite manganites
- Author
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Kajimoto, R., Yoshizawa, H., Kawano-Furukawa, H., Kuwahara, H., Tomioka, Y., and Tokura, Y.
- Subjects
Condensed Matter - Strongly Correlated Electrons - Abstract
Spin wave excitations were measured in the ferromagnetic phase of Nd$_{1/2}$Sr$_{1/2}$MnO$_{3}$ by neutron scattering. This compound is located in proximity to the A-type antiferromagnetic state, and it shows a clear anisotropy and anomalous softening of the spin wave excitations. The softening in the ferromagnetic phase is induced by the orbital ordering., Comment: 2 pages, 1 figure, proceeding of ICM2000. Corrected typos
- Published
- 2000
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33. Influence of Quasi-Bi-Stripe Charge Order on the Resistivity and Magnetism in a Bilayer Manganite La$_{2-2x}$Sr$_{1+2x}$Mn$_{2}$O$_{7}$
- Author
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Kubota, M., Oohara, Y., Yoshizawa, H., Fujioka, H., Shimizu, K., Hirota, K., Moritomo, Y., and Endoh, Y.
- Subjects
Condensed Matter - Strongly Correlated Electrons - Abstract
The charge ordering in the bilayer manganite system La$_{2-2x}$Sr$_{1+2x}$Mn$_{2}$O$_{7}$ with $0.30 \le x \le 0.50$ has been studied by neutron diffraction. The charge order is characterized by the propagation vector parallel to the [1 0 0] direction (MnO$_2$ direction), but the correlation length is short-ranged and extremely anisotropic, being $\sim 0.02a^{*}$ and $\sim 0.2a^{*}$ parallel and perpendicular to the modulation direction, respectively. The observed charge order can be viewed as a quasi-bi-stripe order, and accounts well for the $x$ dependence of the resistivity. The quasi-bistripe order is stable within the ferromagnetic (FM) MnO$_2$ layers in the A-type antiferromagnetic order, but is instabilized by the 3 dimensional FM order., Comment: 11 pages, 5 figures
- Published
- 2000
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34. Charge and spin ordering in Nd{1/3}Sr{2/3}FeO{3}
- Author
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Kajimoto, R., Oohara, Y., Kubota, M., Yoshizawa, H., Park, S. K., Taguchi, Y., and Tokura, Y.
- Subjects
Condensed Matter - Strongly Correlated Electrons - Abstract
We have investigated the charge and spin ordering in Nd{1/3}Sr{2/3}FeO{3} with neutron diffraction technique. This sample undergoes a charge ordering transition accompanying charge disproportionation of 2Fe4+ -> Fe3+ + Fe5+. We measured the superlattice reflections due to the charge and spin ordering, and confirmed that charges and spins order simultaneously at Tco = 185 K. The ordering pattern of charges and spins in this sample can be viewed as three dimensional stripe order, and is compared with two dimensional stripe order observed in other transition metal oxides., Comment: REVTeX, 4 pages, 3 figures, to be published in J. Phys. Chem. Solids
- Published
- 2000
- Full Text
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35. Stripe order at low temperatures in La{2-x}Sr{x}NiO4 for 1/3 < x < 1/2
- Author
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Yoshizawa, H., Kakeshita, T., Kajimoto, R., Tanabe, T., Katsufuji, T., and Tokura, Y.
- Subjects
Condensed Matter - Superconductivity ,Condensed Matter - Strongly Correlated Electrons - Abstract
Stripe order in La{2-x}Sr{x}NiO4 beyond x = 1/3 was studied with neutron scattering technique. At low temperatures, all the samples exhibit hole stripe order. Incommensurability \epsilon of the stripe order is approximately linear in the hole concentration n_h = x + 2\delta up to x = 1/2, where \delta denotes the off-stoichiometry of oxygen atoms. The charge and spin ordering temperatures exhibit maxima at n_h = 1/3, and both decrease beyond n_h > 1/3. For 1/3 < n_h < 1/2, the stripe ordering consists of the mixture of the \epsilon = 1/3 stripe order and the n_h = 1/2 charge/spin order., Comment: REVTeX, 4 pages, 4 figures
- Published
- 1999
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36. Hole concentration induced transformation of the magnetic and orbital structure in Nd{1-x}Sr{x}MnO{3}
- Author
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Kajimoto, R., Yoshizawa, H., Kawano, H., Kuwahara, H., Tokura, Y., Ohoyama, K., and Ohashi, M.
- Subjects
Condensed Matter - Strongly Correlated Electrons - Abstract
In order to study the magnetic and crystal structures in the Nd{1-x}Sr{x}MnO{3} system, we have peformed neutron diffraction measurements on melt-grown polycrystalline samples with 0.49 < x < 0.75. As a function of hole concentration x, the system shows systematic transformation of magnetic and crystal structures, which is consistently explained by the change of the character of Mn eg orbitals. With increasing x, the Nd{1-x}Sr{x}MnO{3} system exhibits a metallic ferromagnetic state, a metallic A-type AFM state, and then an insulating C-type AFM state. The CE-type charge-ordered AFM state was observed only in the vicinity of x=1/2, and it coexists with the A-type AFM state for x > 1/2, indicating that the energy difference between these two states is extremely small. We also found that the MnO{6} octahedra are apically compressed in the CE-type and A-type AFM states due to the d(3x2-r2)/d(3y2-r2) or d(x2-y2) orbital orderings, respectively, whereas they are apically elongated by the rod-type d(3z2-r2) orbital ordering in the C-type AFM state. In addition, a selective broadening of Bragg peaks was observed in the C-type AFM phase, and its x dependence strongly suggests the charge ordering for a commsurate value of the hole concentration at either x=3/4 or x=4/5., Comment: REVTeX, 13 pages, 10 figures, submitted to Phys. Rev. B
- Published
- 1999
- Full Text
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37. Relation between crystal and magnetic structures of the layered manganites La2-2xSr1+2xMn2O7 (0.30 =< x =< 0.50)
- Author
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Kubota, M., Fujioka, H., Hirota, K., Ohoyama, K., Moritomo, Y., Yoshizawa, H., and Endoh, Y.
- Subjects
Condensed Matter - Strongly Correlated Electrons - Abstract
Comprehensive neutron-powder diffraction and Rietveld analyses were carried out to clarify the relation between the crystal and magnetic structures of La2-2xSr1+2xMn2O7 (0.30 =< x =< 0.50). The Jahn-Teller (JT) distortion of Mn-O6 octahedra, i.e., the ratio of the averaged apical Mn-O bond length to the equatorial Mn-O bond length, is Delta_JT=1.042(5) at x=0.30, where the magnetic easy-axis at low temperature is parallel to the c axis. As the JT distortion becomes suppressed with increasing x, a planar ferromagnetic structure appears at x =< 0.32, which is followed by a canted antiferromagnetic (AFM) structure at x =< 0.39. The canting angle between neighboring planes continuously increases from 0 deg (planar ferromagnet: 0.32 =< x < 0.39) to 180 deg (A-type AFM: x=0.48 where Delta_JT=1.013(5)). Dominance of the A-type AF structure with decrease of JT distortion can be ascribed to the change in the eg orbital state from d3z^2-r^2 to dx^2-y^2.
- Published
- 1999
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38. Spin Dynamical Properties of the Layered Perovskite La1.2Sr1.8Mn2O7
- Author
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Fujioka, H., Kubota, M., Hirota, K., Yoshizawa, H., Moritomo, Y., and Endoh, Y.
- Subjects
Condensed Matter - Strongly Correlated Electrons - Abstract
Inelastic neutron-scattering measurements were performed on a single crystal of the layered colossal magnetoresistance (CMR) material La1.2Sr1.8Mn2O7 (Tc ~ 120K). We found that the spin wave dispersion is almost perfectly two-dimensional with the in-plane spin stiffness constant D ~ 151meVA. The value is similar to that of similarly doped La1-xSrxMnO3 though its Tc is three times higher, indicating a large renormalization due to low dimensionality. There exist two branches due to a coupling between layers within a double-layer. The out-of-plane coupling is about 30% of the in-plane coupling though the Mn-O bond lengths are similar., Comment: 3 pages, 3 figures J. Phys. Chem. Solids in press
- Published
- 1999
- Full Text
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39. Neutron Scattering Studies on Magnetic Structure of the Double-Layered Manganite La_{2-2x}Sr_{1+2x}Mn_2O_7 ($0.30 \leq x \leq 0.50$)
- Author
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Kubota, M., Fujioka, H., Ohoyama, K., Hirota, K., Moritomo, Y., Yoshizawa, H., and Endoh, Y.
- Subjects
Condensed Matter - Strongly Correlated Electrons - Abstract
Systematic powder diffraction studies have been carried out to establish the magnetic phase diagram of La_{2-2x}Sr_{1+2x}Mn_2O_7 (LSMO327) in a wide hall concentration range ($0.30 \leq x \leq 0.50$), using the HERMES diffractometer. LSMO327 exhibits a planar ferromagnetic structure for $0.32\leq x\leq 0.38$ at low temperatures. A finite canting angle between planar magnetic moments on neighboring planes starts appearing around $x\sim 0.40$ and reaches 180$^{\circ}$ (A-type antiferromagnet) at x=0.48. At x=0.30, on the other hand, the magnetic moments are aligned parallel to the c-axis., Comment: 3 pages, 3 figures J. Phys. Chem. Solids in press
- Published
- 1999
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40. Interplay of the CE-type charge ordering and the A-type spin ordering in a half-doped bilayer manganite La{1}Sr{2}Mn{2}O{7}
- Author
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Kubota, M., Yoshizawa, H., Moritomo, Y., Fujioka, H., Hirota, K., and Endoh, Y.
- Subjects
Condensed Matter - Strongly Correlated Electrons - Abstract
We demonstrate that the half-doped bilayer manganite La_{1}Sr_{2}Mn_{2}O_{7} exhibits CE-type charge-ordered and spin-ordered states below $T_{N, CO}^A = 210$ K and below $T_{N}^{CE} \sim 145$ K, respectively. However, the volume fraction of the CE-type ordering is relatively small, and the system is dominated by the A-type spin ordering. The coexistence of the two types of ordering is essential to understand its transport properties, and we argue that it can be viewed as an effective phase separation between the metallic $d(x^{2}-y^{2})$ orbital ordering and the charge-localized $d(3x^{2}-r^{2})/d(3y^{2}-r^{2})$ orbital ordering., Comment: 5 pages, 4 figures, submitted to Phys. Rev. B
- Published
- 1998
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41. Anomalous ferromagnetic spin fluctuations in an antiferromagnetic insulator Pr_{1-x}Ca_{x}MnO_{3}
- Author
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Kajimoto, R., Kakeshita, T., Oohara, Y., Yoshizawa, H., Tomioka, Y., and Tokura, Y.
- Subjects
Condensed Matter - Strongly Correlated Electrons - Abstract
The high temperature paramagnetic state in an antiferromagnetic (AFM) insulator Pr_{1-x}Ca_{x}MnO_{3} is characterized by the ferromagnetic (FM) spin fluctuations with an anomalously small energy scale. The FM fluctuations show a precipitous decrease of the intensity at the charge ordering temperature T_{CO}, but persist below T_{CO}, and vanish at the AFM transition temperature T_{N}. These results demonstrate the importance of the spin ordering for the complete switching of the FM fluctuation in doped manganites., Comment: REVTeX, 5 pages, 4 figures, submitted to Phys. Rev. B
- Published
- 1998
- Full Text
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42. Orbital Ordering Induced Antiferromagnetic Spin Fluctuations in the Ferromagnetic State of 50 % Hole-doped Manganites: Pr{1/2}Sr{1/2}MnO3 and Nd{1/2}Sr{1/2}MnO3
- Author
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Kawano, H., Kajimoto, R., Yoshizawa, H., Tomioka, Y., Kuwahara, H., and Tokura, Y.
- Subjects
Condensed Matter - Strongly Correlated Electrons - Abstract
We report inelastic neutron scattering results on the spin dynamics in the 50 % hole-doped manganites, Pr{1/2}Sr{1/2}MnO3 and Nd{1/2}Sr{1/2}MnO3. In the paramagnetic phase, these systems exhibit a ridge-type diffuse scattering, indicating a two-dimensional ferromagnetic (FM) correlation. With decreasing temperature, the systems enter the FM state, but simultaneously they develop A-type antiferromagnetic spin fluctuations. The spin wave dispersion in the FM state is strongly anisotropic. These behaviors can be consistently interpreted from a viewpoint of the underlying orbital ordering., Comment: REVTeX, 4 pages, 4 figures, submitted to Phys. Rev. Lett
- Published
- 1998
43. Spin Chirality, Berry Phase, and Anomalous Hall Effect in a Frustrated Ferromagnet
- Author
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Taguchi, Y., Oohara, Y., Yoshizawa, H., Nagaosa, N., and Tokura, Y.
- Published
- 2001
44. Delivery of microRNA-146a with polyethylenimine nanoparticles inhibits renal fibrosis in vivo
- Author
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Morishita Y, Imai T, Yoshizawa H, Watanabe M, Ishibashi K, Muto S, and Nagata D
- Subjects
Medicine (General) ,R5-920 - Abstract
Yoshiyuki Morishita,1 Toshimi Imai,1 Hiromichi Yoshizawa,1 Minami Watanabe,1 Kenichi Ishibashi,2 Shigeaki Muto,1 Daisuke Nagata1 1Division of Nephrology, Department of Medicine, Jichi Medical University, Tochigi, 2Department of Medical Physiology, Meiji Pharmaceutical University, Tokyo, Japan Abstract: Renal fibrosis is the final common pathway leading to end-stage renal disease. Although microRNA (miR) was recently shown to be involved in the development of renal fibrosis, few studies have focused on the effects on renal fibrosis of exogenous miR delivered in an in vivo therapeutic setting. The study reported here investigated the effects of miR-146a delivery using polyethylenimine nanoparticles (PEI-NPs) on renal fibrosis in vivo. PEI-NPs bearing miR-146 or control-miR (nitrogen/phosphate ratio: 6) were injected into the tail vein of a mouse model of renal fibrosis induced by unilateral ureteral obstruction. PEI-NPs bearing miR-146 significantly enhanced miR-146a expression in the obstructed kidney compared with the control group, while inhibiting the renal fibrosis area, expression of alpha-smooth muscle actin, and infiltration of F4/80-positive macrophages into the obstructed kidney. In addition, PEI-NPs bearing miR-146a inhibited the transforming growth factor beta 1–Smad and tumor necrosis factor receptor-associated factor 6–nuclear factor kappa B signaling pathways. Control-miR-PEI-NPs did not show any of these effects. These results suggest that the delivery of miR-146a attenuated renal fibrosis by inhibiting pro-fibrotic and inflammatory signaling pathways and that the delivery of appropriate miRs may be a therapeutic option for preventing renal fibrosis in vivo. Keywords: miR, end-stage renal disease, pro-fibrotic signaling pathway, inflammatory signaling pathway
- Published
- 2015
45. Reasons for encounter and diagnoses of new outpatients at a small community hospital in Japan: an observational study
- Author
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Takeshima T, Kumada M, Mise J, Ishikawa Y, Yoshizawa H, Nakamura T, Okayama M, and Kajii E
- Subjects
Medicine (General) ,R5-920 - Abstract
Taro Takeshima,1,2 Maki Kumada,3,4 Junichi Mise,5 Yoshinori Ishikawa,6 Hiromichi Yoshizawa,4 Takashi Nakamura,3,4 Masanobu Okayama,1 Eiji Kajii11Division of Community and Family Medicine, Center for Community Medicine, Jichi Medical University, Shimotsuke, Japan; 2Department of Healthcare Epidemiology, School of Public Health in the Graduate School of Medicine, Kyoto University, Kyoto, Japan; 3Division of The Project for Integration of Community Health, Center for Community Medicine, Jichi Medical University, Shimotsuke, Japan; 4Department of General Internal Medicine, Chikusei City Hospital, Chikusei, Japan; 5Division of Human Resources Development for Community Medicine, Center for Community Medicine, Jichi Medical University, Shimotsuke, Japan; 6Department of Surgery, Chikusei City Hospital, Chikusei, JapanPurpose: Although many new patients are seen at small hospitals, there are few reports of new health problems from such hospitals in Japan. Therefore, we investigated the reasons for encounter (RFE) and diagnoses of new outpatients in a small hospital to provide educational resources for teaching general practice methods.Methods: This observational study was conducted at the Department of General Internal Medicine in a small community hospital between May 6, 2010 and March 11, 2011. We classified RFEs and diagnoses according to component 1, “Symptoms/Complaints”, and component 7, “Diagnosis/Diseases”, of the International Classification of Primary Care, 2nd edition (ICPC-2). We also evaluated the differences between RFEs observed and common symptoms from the guidelines Model Core Curriculum for Medical Students and Goals of Clinical Clerkship.Results: We analyzed the data of 1,515 outpatients. There were 2,252 RFEs (1.49 per encounter) and 170 ICPC-2 codes. The top 30 RFE codes accounted for 80% of all RFEs and the top 55 codes accounted for 90%. There were 1,727 diagnoses and 196 ICPC-2 codes. The top 50 diagnosis codes accounted for 80% of all diagnoses, and the top 90 codes accounted for 90%. Of the 2,252 RFEs, 1,408 (62.5%) included at least one of the 36 symptoms listed in the Model Core Curriculum and 1,443 (64.1%) included at least one of the 35 symptoms in the Goals of Clinical Clerkship. On the other hand, “A91 Abnormal result investigation”, “R21 Throat symptom/complaint”, and “R07 Sneezing/nasal congestion”, which were among the top 10 RFEs, were not included in these two guidelines.Conclusion: We identified the common RFEs and diagnoses at a small hospital in Japan and revealed the inconsistencies between the RFEs observed and common symptoms listed in the guidelines. Our findings can be useful in improving the general practice medical education curricula.Keywords: general practice, primary care, medical education, International Classification of Primary Care
- Published
- 2014
46. In-plane anisotropic charge dynamics in the layered polar Dirac semimetal BaMnSb2
- Author
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Yoshizawa, H., primary, Sakai, H., additional, Kondo, M., additional, Ochi, M., additional, Kuroki, K., additional, Hanasaki, N., additional, and Fujioka, J., additional
- Published
- 2022
- Full Text
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47. High durability variable geometry turbine for commercial vehicle turbochargers
- Author
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Gupta, B, primary, Hoshi, T, additional, and Yoshizawa, H, additional
- Published
- 2022
- Full Text
- View/download PDF
48. TGF-β1-siRNA delivery with nanoparticles inhibits peritoneal fibrosis
- Author
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Yoshizawa, H, Morishita, Y, Watanabe, M, Ishibashi, K, Muto, S, Kusano, E, and Nagata, D
- Published
- 2015
- Full Text
- View/download PDF
49. Metastability and a Temporal Phase Transition in the Random Field Ising Model
- Author
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Cowley, R. A., Birgeneau, R. J., Shirane, G., Yoshizawa, H., Pynn, Roger, editor, and Skjeltorp, Arne, editor
- Published
- 1991
- Full Text
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50. Randomized phase II study of concurrent versus sequential alternating gefitinib and chemotherapy in previously untreated non-small cell lung cancer with sensitive EGFR mutations: NEJ005/TCOG0902
- Author
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Sugawara, S., Oizumi, S., Minato, K., Harada, T., Inoue, A., Fujita, Y., Maemondo, M., Yoshizawa, H., Ito, K., Gemma, A., Nishitsuji, M., Harada, M., Isobe, H., Kinoshita, I., Morita, S., Kobayashi, K., Hagiwara, K., Kurihara, M., and Nukiwa, T.
- Published
- 2015
- Full Text
- View/download PDF
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