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Journal Articles

Spin gap in the weakly interacting quantum spin chain antiferromagnet KCuPO $_{4}$ H $_{2}$ O

Fujihara, Masayoshi; Hagihara, Masato; Morita, Katsuhiro*; Murai, Naoki; Koda, Akihiro*; Okabe, Hirotaka*; Mitsuda, Setsuo*

Physical Review B, 107(5), p.054435_1 - 054435_8, 2023/02

https://doi.org/10.1103/PhysRevB.107.054435

Times Cited Count：0 Percentile：0(Materials Science, Multidisciplinary)

The = 1/2 Heisenberg linear chain antiferromagnet is the simplest spin model; nevertheless it serves as a platform for various quantum many-body phenomena. Here, we report the magnetic behavior of a quasi-one-dimensional antiferromagnet KCuPO $_{4}$ H $_{2}$ O. A long-range commensurate antiferromagnetic order with ordered moment 0.31(1) $mu_{rm{B}}$ per spin occurs at $T_{rm{N}}$ = 11.7(1) K. Above $T_{rm{N}}$ , the inelastic neutron excitation is characterized by a two spinon continuum. The intrachain interaction and interchain interaction are estimated to be 172 K and 4.25(4) K, respectively; thus the ratio of the / = 0.0247(3). At lower energies, below $T_{rm{N}}$ , a spin gap is observed in the dispersive excitations. These results are consistent with characteristics observed in weakly interacting = 1/2 Heisenberg chain system.

Journal Articles

Birchite Cd $_{2}$ Cu $_{2}$ (PO $_{4}$ ) $_{2}$ SO $_{4}$ 5H $_{2}$ O as a model antiferromagnetic spin-1/2 Heisenberg $_{1}$ - $_{2}$ chain

Fujihara, Masayoshi; Jeschke, H. O.*; Morita, Katsuhiro*; Kuwai, Tomohiko*; Koda, Akihiro*; Okabe, Hirotaka*; Matsuo, Akira*; Kindo, Koichi*; Mitsuda, Setsuo*

Physical Review Materials (Internet), 6(11), p.114408_1 - 114408_8, 2022/11

https://doi.org/10.1103/PhysRevMaterials.6.114408

Times Cited Count：0 Percentile：0(Materials Science, Multidisciplinary)

= 1/2 Heisenberg $_{1}$ - $_{2}$ chain antiferromagnets have been investigated extensively due to their exotic magnetic states. Here, we report the magnetic behavior of birchite Cd $_{2}$ Cu $_{2}$ (PO $_{4}$ ) $_{2}$ SO $_{4}$ 5H $_{2}$ O and its effective spin model. Experimental studies by magnetic susceptibility, magnetization, heat capacity, and SR measurements indicate the absence of long-range order down to 0.4 K. Theoretical studies reveal that birchite is a model compound for the $_{1}$ - $_{2}$ antiferromagnetic chain: the intrachain interactions $_{1}$ and $_{2}$ are antiferromagnetic and their magnitude is about 100 times larger than the interchain interactions. The magnitude of $_{2}$ is two to three times larger than that of $_{1}$ , thus the spin gap is expected to be only a few percent of that of $_{1}$ . The temperature dependence of the specific heat shows a broad peak at about 1 K ( 0.036 $_{1}$ ), which suggests the presence of a spin gap.

Journal Articles

Magnon pairs and spin-nematic correlation in the spin Seebeck effect

Hirobe, Daichi*; Sato, Masahiro*; Hagihara, Masato*; Shiomi, Yuki*; Masuda, Takatsugu*; Saito, Eiji

Physical Review Letters, 123(11), p.117202_1 - 117202_7, 2019/09

https://doi.org/10.1103/PhysRevLett.123.117202

Times Cited Count：14 Percentile：65.02(Physics, Multidisciplinary)

Journal Articles

Spin, charge, and orbital correlations in the one-dimensional $t_{rm 2g}$ -orbital Hubbard model

Xavier, J. C.*; Onishi, Hiroaki; Hotta, Takashi; Dagotto, E.*

Physical Review B, 73(1), p.014405_1 - 014405_9, 2006/01

https://doi.org/10.1103/PhysRevB.73.014405

Times Cited Count：9 Percentile：41.55(Materials Science, Multidisciplinary)

We present the zero-temperature phase diagram of the one-dimensional $t_{rm 2g}$ -orbital Hubbard model, by using the density-matrix renormalization group and Lanczos techniques. Emphasis is given to the case for the electron density =5, of relevance to Co-based compounds. Several other cases for electron densities between =3 and 6 are also studied. At =5, our results indicate a first-order transition between a paramagnetic (PM) insulator phase and a ferromagnetic (FM) state by tuning the Hund's coupling. The results also suggest a transition from the =5 PM insulator phase to a metallic regime by changing the electron density. The behavior of the spin, charge, and orbital correlation functions in the FM and PM states are discussed.

Journal Articles

Polarized neutron scattering study of the CuO $_{2}$ chains in Ca $_{2}$ Y $_{2}$ Cu $_{5}$ O $_{10}$

Matsuda, Masaaki; Nakamura, Mitsutaka; Takeda, Masayasu*; Kakurai, Kazuhisa; Yamaguchi, Hirotaka*; Ito, Toshimitsu*; Oka, Kunihiko*

Physica B; Condensed Matter, 329-333(1-4), p.711 - 712, 2003/05

https://doi.org/10.1016/S0921-4526(02)02020-3

Times Cited Count：0 Percentile：0(Physics, Condensed Matter)

no abstracts in English

Journal Articles

Detailed magnetic structure of the coupled edge-sharing CuO $_{2}$ chains in Ca $_{2+x}$ Y $_{2-x}$ Cu $_{5}$ O $_{10}$

Matsuda, Masaaki; Kakurai, Kazuhisa; Yamaguchi, Hirotaka*; Ito, Toshimitsu*; Lee, C.-H.*; Oka, Kunihiko*

Applied Physics A, 74(Suppl.1), p.S637 - S639, 2002/12

https://doi.org/10.1007/s003390201569

Times Cited Count：3 Percentile：16.11(Materials Science, Multidisciplinary)

no abstracts in English

Journal Articles

Photoemission study of quasi-one-dimensional halogen-bridged compound [Ni(chxn) $_{2}$ Br]Br $_{2}$

Fujimori, Shinichi; Ino, Akihiro; Okane, Tetsuo; Fujimori, Atsushi; Okada, Kozo*; Manabe, Toshio*; Yamashita, Masahiro*; Kishida, Hideo*; Okamoto, Hiroshi*

Surface Review and Letters, 9(2), p.1065 - 1069, 2002/04

https://doi.org/10.1142/S0218625X02003354

Times Cited Count：0 Percentile：0(Chemistry, Physical)

no abstracts in English

Journal Articles

Magnetic properties of (Mn $_{1-x}$ V $_{x}$ )Sb $_{2}$ O $_{4}$ with one-dimensional magnetic arrays

Abe, Hideki*; Yoshii, Kenji; Kitazawa, Hideaki*

Physica Status Solidi (A), 189(2), p.429 - 432, 2002/02

https://doi.org/10.1002/1521-396X(200202)189:2<429::AID-PSSA429>3.0.CO;2-8

Times Cited Count：1 Percentile：7.78(Materials Science, Multidisciplinary)

no abstracts in English

JAEA Reports

Theoretical background and user's manual for the computer code on groundwater flow and radionuclide transport calculation in porous rock

JNC TN8400 2001-027, 131 Pages, 2001/11

JNC-TN8400-2001-027.pdf:0.8MB

In order to document a basic manual about input data, output data, execution of computer code on groundwater flow and radionuclide transport calculation in heterogeneous porous rock, we investigated the theoretical background about geostastical computer codes and the user's manual for the computer code on groundwater flow and radionuclide transport which calculates water flow in three dimension, the path of moving radionuclide, and one dimensional radionuclide migration. In this report, based on above investigation we describe the geostastical background about simulating heterogeneous permeability field. And we describe construction of files, input and output data, a example of calculating of the programs which simulates heterogeneous permeability field, and calculates groundwater flow and radionuclide transport. Therefore, we can document a manual by investigating the theoretical background about geostastical computer codes and the user's manual for the computer code on groundwater flow and radionuclide transport calculation. And we can model heterogeneous porous rock and analyze groundwater flow and radionuclide transport by utilizing the information from this report.

Journal Articles

Partially disordered antiferromagnetic phase in Ca $_{3}$ CoRhO $_{6}$

Niitaka, Seiji*; Yoshimura, Kazuyoshi*; Kosuge, K.*; Nishi, Masakazu*; Kakurai, Kazuhisa

Physical Review Letters, 87(17), p.177202_1 - 177202_4, 2001/10

https://doi.org/10.1103/PhysRevLett.87.177202

Times Cited Count：97 Percentile：91.61(Physics, Multidisciplinary)

no abstracts in English

Journal Articles

Upgrade of the wide-angle neutron diffractometer at the high-flux isotope reactor

Ishii, Yoshinobu; Katano, Susumu; Suzuki, Junichi; Aizawa, Kazuya; Child, H. R.*; Morii, Yukio; Fernandez-Baca, J. A.*

Journal of the Physical Society of Japan, Vol.70, Supplement A, p.453 - 455, 2001/05

no abstracts in English

JAEA Reports

Reliability evaluation of simulation models for nearfield groundwater flow and radionuclide transport computation

*; *; *; *

JNC TJ8400 2000-005, 71 Pages, 2000/05

JNC-TJ8400-2000-005.pdf:4.0MB

In this research, simulations with some parameters which characterize ground water flow and the reliability evaluation for the expansion of the calculation method of groundwater flow were carried out by using the radionuclide transport computations in nearfield heterogeneous porous media. Concretely contents are follows: (1)With the series of calculation method for three-dimensional saturated/unsaturated groundwater flow and one-dimensional radionuclide transport, the computational analyses with the parameters used in JNC report in 2000 was carried out and the influence of the different input flux was evaluated. (2)The examination of the application for the different ways of inverse laplace transformation which is used in one-dimensional radionuclide transport analysis code "MATRICS" was carried out. (3)The examination of the application of multi-element "MATRICS" (m-MATRICS) for radionuclide transport computations in nearfield heterogeneous porous media was carried out. (4)The series of calculation methods from three-dimensional saturated/unsaturated ground water flow simulation code to one-dimensional radionuclide transport simulation code was integrated.

JAEA Reports

Nuclide migration analysis in fractured rock

Sawada, Atsushi; Ijiri, Yuji; *; Watari, Shingo

JNC TN8400 99-093, 58 Pages, 1999/11

JNC-TN8400-99-093.pdf:11.24MB

This paper decribes the results of PA studies considering heterogeneous fracture characteristics, for the purpose of contributing for the performance assessment of the natural barrier system PA in H12 report (The second progress report on research and development for the Geological Disposal of HLW in Japan). In this study, 3-D discrete fracture network mode1 (DFN) and 1-D multiple pathways model is applied for 100m scale of rock block. Although nuclide release rate calculated by DFN are widely distributed among the realizations, it is shown that several tens realizations are enough number to understand the stochastic characteristics of the nuclide release. From the data uncertainty analysis, there are no significant effects for the nuclide retardation in fracture geometry parameters such as fracture radius, density and etc. 1-D multiple pathways model is developed with focusing on the heterogeneity of the transmissivity, which has a large effect to the nuclide retardation effects. The nuclide release rate calculated by using 1-D multiple pathways model approximates to the results of DFN. This result also shows that the relatively large fractures/faults that connects disposal tunnel and downstream faults have an important role for performance assessment in natural barrier system.

Journal Articles