2018

Magnetic state selected by magnetic dipole interaction in the kagome antiferromagnet NaBa2Mn3F11

S. Hayashida, H. Ishikawa, Y. Okamoto, T. Okubo, Z. Hiroi, M. Avdeev, P. Manuel, M. Hagihala, M. Soda and T. Masuda

Phys. Rev. B 97, 054411 (2018); https://link.aps.org/doi/10.1103/PhysRevB.97.054411

2017

Spin dynamics in the high-field phases of volborthite

M. Yoshida, K. Nawa, H. Ishikawa, M. Takigawa, M. Jeong, S. Krämer, M. Horvatić, C. Berthier, K. Matsui, T. Goto, S. Kimura, T. Sasaki, J. Yamaura, H. Yoshida, Y. Okamoto and Z. Hiroi

Phys. Rev. B 96, 180413 (2017); https://link.aps.org/doi/10.1103/PhysRevB.96.180413

Classical Spin Nematic Transition in LiGa0.95In0.05Cr4O8

R. Wawrzyńczak, Y. Tanaka, M. Yoshida, Y. Okamoto, P. Manuel, N. Casati, Z. Hiroi, M. Takigawa and G. J. Nilsen

Phys. Rev. Lett. 119, 087201/1-5 (2017); https://link.aps.org/doi/10.1103/PhysRevLett.119.087201

Strong Spin-Phonon Coupling Mediated by Single Ion Anisotropy in the All-In\All-Out Pyrochlore Magnet Cd2Os2O7

C. H. Sohn, C. H. Kim, L. J. Sandilands, N. T. M. Hien, S. Y. Kim, H. J. Park, K. W. Kim, S. J. Moon, J. Yamaura, Z. Hiroi and T. W. Noh

Phys. Rev. Lett. 118, 117201 (2017); https://link.aps.org/doi/10.1103/PhysRevLett.118.117201

Magnetic transitions under ultrahigh magnetic fields of up to 130 T in the breathing pyrochlore antiferromagnet LiInCr4O8

Y. Okamoto, D. Nakamura, A. Miyake, S. Takeyama, M. Tokunaga, A. Matsuo, K. Kindo and Z. Hiroi

Phys. Rev. B 95, 134438/1-5 (2017); https://link.aps.org/doi/10.1103/PhysRevB.95.134438

Phase diagram of multiferroic KCu3As2O7(OD)3

G. J. Nilsen, V. Simonet, C. V. Colin, R. Okuma, Y. Okamoto, M. Tokunaga, T. C. Hansen, D. D. Khalyavin and Z. Hiroi

Phys. Rev. B 95, 214415/1-10 (2017); https://link.aps.org/doi/10.1103/PhysRevB.95.214415

Two-magnon scattering in the 5d all-in-all-out pyrochlore magnet Cd2Os2O7

T. M. H. Nguyen, L. J. Sandilands, C. H. Sohn, C. H. Kim, A. L. Wysocki, I.-S. Yang, S. J. Moon, J.-H. Ko, J. Yamaura, Z. Hiroi and T. W. Noh

Nat. Commun. 8, 251/1-8 (2017); https://doi.org/10.1038/s41467-017-00228-w

Anisotropic field-induced gap in the quasi-one-dimensional antiferromagnet KCuMoO4OH

K. Nawa, O. Janson and Z. Hiroi

Phys. Rev. B 96, 104429/1-10 (2017); https://link.aps.org/doi/10.1103/PhysRevB.96.104429

Maximizing Tc by tuning nematicity and magnetism in FeSe1−xSx superconductors

K. Matsuura, Y. Mizukami, Y. Arai, Y. Sugimura, N. Maejima, A. Machida, T. Watanuki, T. Fukuda, T. Yajima, Z. Hiroi, K. Y. Yip, Y. C. Chan, Q. Niu, S. Hosoi, K. Ishida, K. Mukasa, S. Kasahara, J. G. Cheng, S. K. Goh, Y. Matsuda, Y. Uwatoko and T. Shibauchi

Nat. Commun. 8, 1143 (2017); https://doi.org/10.1038/s41467-017-01277-x

High-pressure Raman study on the superconducting pyrochlore oxide Cd2Re2O7

Y. Matsubayashi, T. Hasegawa, N. Ogita, J. Yamaura and Z. Hiroi

Physica B, in press (2017); http://www.sciencedirect.com/science/article/pii/S0921452617307639

Topochemical Crystal Transformation from a Distorted to a Nearly Perfect Kagome Cuprate

H. Ishikawa, T. Yajima, A. Miyake, M. Tokunaga, A. Matsuo, K. Kindo and Z. Hiroi

Chem. Mater. 29, 6719 (2017); http://dx.doi.org/10.1021/acs.chemmater.7b01448

Weak ferromagnetic order breaking the threefold rotational symmetry of the underlying kagome lattice in CdCu3(OH)6(NO3)2 · H2O

R. Okuma, T. Yajima, D. Nishio-Hamane, T. Okubo and Z. Hiroi

Phys. Rev. B 95, 094427 (2017); http://link.aps.org/doi/10.1103/PhysRevB.95.094427

Robust ferromagnetism carried by antiferromagnetic domain walls

H. T. Hirose, J.-i. Yamaura and Z. Hiroi

Scientific Reports 7, 42440 (2017); http://dx.doi.org/10.1038/srep42440

Successive spatial symmetry breaking under high pressure in the spin-orbit-coupled metal Cd2Re2O7

J. Yamaura, K. Takeda, Y. Ikeda, N. Hirao, Y. Ohishi, T. C. Kobayashi and Z. Hiroi

Phys. Rev. B 95, 020102 (2017); http://link.aps.org/doi/10.1103/PhysRevB.95.020102

J1−J2  square-lattice Heisenberg antiferromagnets with 4d1 spins: AMoOPO4Cl (A = K, Rb)

H. Ishikawa, N. Nakamura, M. Yoshida, M. Takigawa, P. Babkevich, N. Qureshi, H. M. Rønnow, T. Yajima and Z. Hiroi

Phys. Rev. B 95, 064408 (2017); http://link.aps.org/doi/10.1103/PhysRevB.95.064408

2016

Emergence of nontrivial magnetic excitations in a spin-liquid state of kagomé volborthite

D. Watanabe, K. Sugii, M. Shimozawa, Y. Suzuki, T. Yajima, H. Ishikawa, Z. Hiroi, T. Shibauchi, Y. Matsuda and M. Yamashita

PNAS 113, 8653 (2016); 10.1073/pnas.1524076113

二酸化バナジウムVO2の金属絶縁体転移再考 —分子軌道結晶ー：固体物理51, 1 (2016)

2015

Complex magnetostructural order in the frustrated spinel LiInCr4O8

G. J. Nilsen, Y. Okamoto, T. Masuda, J. Rodriguez-Carvajal, H. Mutka, T. Hansen and Z. Hiroi

Phys. Rev. B 91, 174435 (2015); http://dx.doi.org/10.1103/PhysRevB.91.174435

All-In–All-Out Magnetic Domains: X-Ray Diffraction Imaging and Magnetic Field Control

    S. Tardif, S. Takeshita, H. Ohsumi, J. Yamaura, D. Okuyama, Z. Hiroi, M. Takata and T. Arima

    Phys. Rev. Lett. 114, 147205 (2015); 10.1103/PhysRevLett.114.147205

Spinodally-decomposed nanostructures in a TiO2–VO2 crystal

    Z. Hiroi, T. Yoshida, J. Yamaura and Y. Okamoto

    APL Materials, in press.

Lifshitz metal–insulator transition induced by the all-in/all-out magnetic order in the pyrochlore oxide Cd2Os2O7

    Z. Hiroi, J. Yamaura, T. Hirose, I. Nagashima and Y. Okamoto

    APL Materials 3, 041501 (2015); http://dx.doi.org/10.1063/1.4907734

Structural instability of the rutile compounds and its relevance to the metal–insulator transition of VO2

    Z. Hiroi

    Prog. Solid State Chem. 43, 47 (2015); 10.1016/j.progsolidstchem.2015.02.001

2014

Kagome–Triangular Lattice Antiferromagnet NaBa2Mn3F11

    H. Ishikawa, T. Okubo, Y. Okamoto and Z. Hiroi

    J. Phys. Soc. Jpn. 83, 043703 (2014); 10.7566/JPSJ.83.043703

Electronic State of CeFe4As12 Investigated by Using Single Crystals Grown under High Pressure of 4 GPa

    Y. Ogawa, H. Sato, M. Watanabe, T. Namiki, S. Tatsuoka, R. Higashinaka, Y. Aoki, K. Kuwahara, J.-I. Yamaura and Z. Hiroi

    J. Phys. Soc. Jpn. 83, 034710 (2014); 10.7566/JPSJ.83.034710

Novel Phase Transitions in the Breathing Pyrochlore Lattice: 7Li−NMR on LiInCr4O8 and LiGaCr4O8

    Y. Tanaka, M. Yoshida, M. Takigawa, Y. Okamoto and Z. Hiroi

    Phys. Rev. Lett. 113, 227204 (2014); 10.1103/PhysRevLett.113.227204

Novel rattling of K atoms in aluminium-doped defect pyrochlore tungstate

    E. Shoko, G. J. Kearley, V. K. Peterson, H. Mutka, M. M. Koza, J. Yamaura, Z. Hiroi and G. J. Thorogood

    Journal of Physics-Condensed Matter 26  (2014); 10.1088/0953-8984/26/30/305401

Helical order and multiferroicity in the Helical order and multiferroicity in the S = 1/2 quasi-kagome system KCu3As2O7(OD)3

    G. J. Nilsen, Y. Okamoto, H. Ishikawa, V. Simonet, C. V. Colin, A. Cano, L. C. Chapon, T. Hansen, H. Mutka and Z. Hiroi

    Phys. Rev. B 89, 140412 (2014); 10.1103/PhysRevB.89.140412

NaCuMoO4(OH) as a Candidate Frustrated J1–J2 Chain Quantum Magnet

    K. Nawa, Y. Okamoto, A. Matsuo, K. Kindo, Y. Kitahara, S. Yoshida, S. Ikeda, S. Hara, T. Sakurai, S. Okubo, H. Ohta and Z. Hiroi

    J. Phys. Soc. Jpn. 83, 103702/1-5 (2014); 10.7566/JPSJ.83.103702

Spin dynamics of Mn pyrochlore lattice in YMn2Zn20-xInx

    M. Miyazaki, R. Kadono, M. Hiraishi, I. Yamauchi, A. Koda, K. M. Kojima, I. Kawasaki, I. Watanabe, Y. Okamoto and Z. Hiroi

    J. Phys: Conf. Ser. 551, 012019 (2014); 10.1088/1742-6596/551/1/012019

Thermoelectric properties of Sr and Mg double-substituted LaCoO3 at room temperature

    A. Jiamprasertboon, Y. Okamoto, Z. Hiroi and T. Siritanon

    Ceramics International 40, 12729 (2014); 10.1016/j.ceramint.2014.04.123

2013

Spinodal Decomposition in the TiO2–VO2 System

    Z. Hiroi, H. Hayamizu, T. Yoshida, Y. Muraoka, Y. Okamoto, J. Yamaura, Y. Ueda

    Chem. Mater. 25, 2202/2202-2210, (2013).

Breathing Pyrochlore Lattice Realized in A-Site Ordered Spinel Oxides LiGaCr_{4}O_{8} and LiInCr_{4}O_{8}

Y. Okamoto, G. r. J. Nilsen, J. P. Attfield and Z. Hiroi

Physical Review Letters 110(9), 097203 (2013).

Understanding of the Temperature-Pressure Phase Diagram of beta-Pyrochlore Oxides: A Role of Anhamonicity on Superconductivity

    T. Isono, D. Iguchi, T. Matsubara, Y. Machida, B. Salce, J. Flouquet, H. Ogusu, J. Yamaura, Z. Hiroi, K. Izawa

    J. Phys. Soc. Jpn. 82, 114708/1-9, (2013).

Pressure Effects on Rattling and Superconductivity in the Einstein Solids

    Y. Ikeda, Y. Kawasaki, T. Shinohara, S. Araki, T. C. Kobayashi, A. Onosaka, Y. Okamoto, J. Yamaura, Z. Hiroi,

    J. Phys. Soc. Jpn. 82, 063707/1-4, (2013).

YCr$_{6}$Ge$_{6}$ as a Candidate Compound for a Kagome Metal

Y. Ishii, H. Harima, Y. Okamoto, J.-i. Yamaura and Z. Hiroi

Journal of the Physical Society of Japan 82(Copyright (C) 2013 The Physical Society of Japan), 023705 (2013).

2012

Large Diamagnetism of AV$_{2}$Al$_{20}$ ($\text{A}=\text{Y}$ and La)

A. Onosaka, Y. Okamoto, J.-i. Yamaura, T. Hirose and Z. Hiroi

Journal of the Physical Society of Japan 81, 123702 (2012).

Rattling and Superconducting Properties of the Cage Compound Ga$_{x}$V$_{2}$Al$_{20}$

Z. Hiroi, A. Onosaka, Y. Okamoto, J.-i. Yamaura and H. Harima

Journal of the Physical Society of Japan 81, 124707 (2012).

Study on the Microstructures and the Magnetic Properties of Precipitates in a Cu-75-Fe-5-Ni-20 Alloy

S. Kang, M. Takeda, M. Takeguchi, Z. Hiroi, G. W. Kim, D. S. Bae, C. G. Lee and B. H. Koo, Journal of Nanoscience and Nanotechnology 12(2), 1337-1340 (2012).

A novel crystal polymorph of volborthite, Cu3V2O7(OH)2.2H2O

H. Ishikawa, J.-i. Yamaura, Y. Okamoto, H. Yoshida, G. J. Nilsen and Z. Hiroi

Acta Crystallographica Section C 68(7), i41-i44 (2012).

Study on the Microstructures and the Magnetic Properties of Precipitates in a Cu-75-Fe-5-Ni-20 Alloy

S. Kang, M. Takeda, M. Takeguchi, Z. Hiroi, G. W. Kim, D. S. Bae, C. G. Lee and B. H. Koo

Journal of Nanoscience and Nanotechnology 12(2), 1337-1340 (2012).

Giant Phonon Softening and Enhancement of Superconductivity by Phosphorus Doping of BaNi_{2}As_{2}

K. Kudo, M. Takasuga, Y. Okamoto, Z. Hiroi and M. Nohara

Physical Review Letters 109(9), 097002 (2012).

Spin Reorientation in the Square-Lattice Antiferromagnets RMnAsO (R = Ce, Nd): Density Functional Analysis of the Spin-Exchange Interactions between the Rare-Earth and Transition-Metal Ions

C. Lee, E. Kan, H. Xiang, R. K. Kremer, S.-H. Lee, Z. Hiroi and M.-H. Whangbo

Inorganic Chemistry 51(12), 6890-6897 (2012).

Distorted Kagome Lattice Generated by a Unique Orbital Arrangement in the Copper Mineral KCu$_{3}$As$_{2}$O$_{7}$(OH)$_{3}$

Y. Okamoto, H. Ishikawa, G. Nilsen, oslash, J. ran and Z. Hiroi

Journal of the Physical Society of Japan 81, 033707 (2012).

Crystal chemistry and magnetic properties of manganese zinc alloy “YMn2Zn20” comprising a Mn pyrochlore lattice

Y. Okamoto, T. Shimizu, J.-i. Yamaura and Z. Hiroi

Journal of Solid State Chemistry 191(0), 246-256 (2012).

Large and homogeneous mass enhancement in the rattling-induced superconductor KOs_{2}O_{6}

T. Terashima, N. Kurita, A. Kiswandhi, E.-S. Choi, J. S. Brooks, K. Sato, J. Yamaura,       Z. Hiroi, H. Harima and S. Uji

Physical Review B 85(18), 180503 (2012).

The spin dynamics in distorted kagome lattices: a comparative Raman study

D. Wulferding, P. Lemmens, H. Yoshida, Y. Okamoto and Z. Hiroi

Journal of Physics: Condensed Matter 24(18), 185602 (2012).

Tetrahedral Magnetic Order and the Metal-Insulator Transition in the Pyrochlore Lattice of Cd_{2}Os_{2}O_{7}

J. Yamaura, K. Ohgushi, H. Ohsumi, T. Hasegawa, I. Yamauchi, K. Sugimoto, S. Takeshita, A. Tokuda, M. Takata, M. Udagawa, M. Takigawa, H. Harima, T. Arima and Z. Hiroi

Physical Review Letters 108(24), 247205 (2012).

Orbital switching in a frustrated magnet

H. Yoshida, J. Yamaura, M. Isobe, Y. Okamoto, G. J. Nilsen and Z. Hiroi

Nature Communications 3, 860 (2012).

High-Field Phase Diagram and Spin Structure of Volborthite Cu$_{3}$V$_{2}$O$_{7}$(OH)$_{2}$$\cdot$2H$_{2}$O

M. Yoshida, M. Takigawa, Kr, auml, S. mer, S. Mukhopadhyay, Horvati, Mladen, C. Berthier, H. Yoshida, Y. Okamoto and Z. Hiroi

Journal of the Physical Society of Japan 81(Copyright (C) 2012 The Physical Society of Japan), 024703 (2012).

Superconductivity in the Einstein Solid AxV2Al20 (A = Al and Ga)

A. Onosaka, Y. Okamoto, J. Yamaura and Z. Hiroi

Journal of the Physical Society of Japan 81, 023703 (2012).

Rattling Good Superconductor: the β-Pyrochlore Oxide AOs2O6

Z. Hiroi, J. Yamaura and K. Hattori

Journal of the Physical Society of Japan 81, 011012 (2012).

2011

Heterogeneous spin state in the field-induced phase of volborthite as seen via ^{51}V nuclear magnetic resonance

M. Yoshida, M. Takigawa, H. Yoshida, Y. Okamoto and Z. Hiroi

Physical Review B 84(2), 020410 (2011).

Rattling Vibrations Observed by Means of Single-Crystal X-ray Diffraction in the Filled Skutterudite <i>R</i>Os₄Sb₁₂ (<i>R</i> = La, Ce, Pr, Nd, Sm)

J. Yamaura and Z. Hiroi

Journal of the Physical Society of Japan 80, 054601 (2011).

A magnetic transition probed by the Ce ion in square-lattice

antiferromagnet CeMnAsO

Y. Tsukamoto, Y. Okamoto, K. Matsuhira, M.-H. Whangbo and Z. Hiroi

J. Phys. Soc. Jpn. 80(9), 094708 (2011).

Superconductivity and Rattling under High Pressure in the ß-Pyrochlore Oxide RbOs2O6

N. Takeshita, H. Ogusu, J. Yamaura, Y. Okamoto and Z. Hiroi

Journal of the Physical Society of Japan 80, 104708 (2011).

Magnetization plateaus of the spin-1/2 kagome antiferromagnets volborthite and vesignieite

Y. Okamoto, M. Tokunaga, H. Yoshida, A. Matsuo, K. Kindo and Z. Hiroi

Physical Review B 83(18), 180407 (2011).

Elastic properties of the rare-earth dititanates R2Ti2O7 (R=Tb, Dy, and Ho)

Y. Nakanishi, T. Kumagai, M. Yoshizawa, K. Matsuhira, S. Takagi and Z. Hiroi

Physical Review B 83(18), 184434 (2011).

Spin Dynamics at Very Low Temperature in Spin Ice Dy$_{2}$Ti$_{2}$O$_{7}$

K. Matsuhira, C. Paulsen, E. Lhotel, C. Sekine, Z. Hiroi and S. Takagi

Journal of the Physical Society of Japan 80, 123711 (2011).

Orbital magnetism in Cd_{2}Os_{2}O_{7} studied by x-ray magnetic circular dichroism

Y. H. Matsuda, J. L. Her, S. Michimura, T. Inami, M. Suzuki, N. Kawamura, M. Mizumaki, K. Kindo, J. Yamauara and Z. Hiroi

Physical Review B 84(17), 174431 (2011).

Superconductivity of Heavy Carriers in the Pressure-Induced Phases of Cd₂Re₂O₇

T. C. Kobayashi, Y. Irie, J. Yamaura, Z. Hiroi and K. Murata

Journal of the Physical Society of Japan 80, 023715 (2011).

Low-temperature specific heat of the [beta]-pyrochlore oxide superconductors under high pressure

T. Isono, D. Iguchi, Y. Machida, K. Izawa, B. Salce, J. Flouquet, H. Ogusu, J. Yamaura and Z. Hiroi

Physica E 43(3), 726-729 (2011).

Crystal Structure and Superconductivity of β-Pyrochlore Oxides under High Pressure

T. Isono, Y. Hara, D. Iguchi, Y. Machida, K. Izawa, S. Tsutsui, T. Matsuoka, Y. Ohishi, B. Salce, J. Flouquet, H. Ogusu, J. Yamaura and Z. Hiroi

J. Phys. Soc. Jpn. 80(Proceedings of the International Conference on Heavy Electrons 2010 (ICHE2010)), SA041 (2011).

Anisotropic vortex pinning in the β-pyrochlore oxide superconductor KOs2O6

Y. Ishii, J. Yamaura, Y. Okamoto, A. Maeda and Z. Hiroi

Physica C: Superconductivity 471(21-22), 801-803 (2011).

Pressure Dependence of Upper Critical Field in β-Pyrochlore Oxides

D. Iguchi, T. Isono, Y. Machida, K. Izawa, B. Salce, J. Flouquet, H. Ogusu, J. Yamaura and Z. Hiroi

J. Phys. Soc. Jpn. 80(Proceedings of the International Conference on Heavy Electrons 2010 (ICHE2010)), SA040 (2011).

Novel magnetic order in the kagome lattice of volborthite

Z. Hiroi, H. Yoshida, Y. Okamoto and M. Yoshida

J. Phys.: Conf. Series, in press. (2011).

2010

High-Field ESR Measurements of S=1/2 Kagome Lattice ¥¥ Antiferromagnet $¥mathrm{BaCu_3V_2O_8(OH)_2}$

W.-m. Zhang, H. Ohta, S. Okubo, M. Fujisawa, T. Sakurai, Y. Okamoto, H. Yoshida and Z. Hiroi

J. Phys. Soc. Jpn 79, 023708 (2010).

Isomorphic structural transition in the ß-pyrochlore oxide superconductor KOs2O6

J. Yamaura, M. Takigawa, O. Yamamuro and Z. Hiroi

J. Phys. Soc. Jpn. 79, 043601 (2010).

Thermodynamic Properties of the Kagome Lattice in Volborthite

S. Yamashita, T. Moriura, Y. Nakazawa, H. Yoshida, Y. Okamoto and Z. Hiroi

Journal of the Physical Society of Japan 79, 083710 (2010).

The relationship between the microstructure and the magnetic properties of nano-scale magnetic particles in a Cu–Fe–Co ternary alloy

N. Wada, Y. Azuma, M. Takeda and Z. Hiroi

Int. J. Mat. Res. 101, 356-360 (2010).

Rare-earth atom motions in ROs4Sb12 (R = La, Pr, Nd, Sm)

S. Tsutsui, H. Uchiyama, J. P. Sutter, A. Q. R. Baron, H. Sugawara, J. Yamaura, Z. Hiroi, A. Ochiai and H. Sato

Journal of Physics: Conference Series 200(1), 012213 (2010).

Superconducting weak link generated at atomic steps on a substrate in a YBa2Cu3O7-δ ultrathin film

A. Tsurumaki and Z. Hiroi

Physica C 207, S863–S864 (2010).

Synthesis and physical properties of CeFe1−xMxAsO (M=Mn,Co)

Y. Tsukamoto, Y. Okamoto and Z. Hiroi

Physica C 470, S445–S446 (2010).

Upper Critical Field and de Haas van Alphen Oscillations in KOs2O6 Measured in a Hybrid Magnet

T. Terashima, N. Kurita, A. Harada, K. Kodama, J. Yamaura, Z. Hiroi, H. Harima and S. Uji

Journal of the Physical Society of Japan 79(Copyright (C) 2010 The Physical Society of Japan), 083703 (2010).

A novel isomorphic phase transition in ß-pyrochlore oxide KOs2O6: a study using high resolution neutron powder diffraction

K. Sasai, M. Kofu, R. M. Ibberson, K. Hirota, J. Yamaura, Z. Hiroi and O. Yamamuro

Journal of Physics: Condensed Matter 22(1), 015403 (2010).

Itinerant-Electron Magnet of the Pyrochlore Lattice: Indium-Doped YMn2Zn20

Y. Okamoto, T. Shimizu, J. Yamaura, Y. Kiuchi and Z. Hiroi

J. Phys. Soc. Jpn. 79(9), 093712 (2010).

Discontinuous Lifshitz transition achieved by band-filling control in NaxCoO2

Y. Okamoto, A. Nishio and Z. Hiroi

Physical Review B 81(12), 121102 (2010).

Spin dynamics of S¼1/2 kagome lattice antiferromagnets observed by high-field ESR

H. Ohta, W.-m. Zhang, S. Okubo, M. Fujisawa, T. Sakurai, Y. Okamoto, H. Yoshida and Z. Hiroi

Phys. Status Solidi B 247, 679-681 (2010).

High-pressure resistivity measurements on the β-pyrochlore oxide KOs2O6

H. Ogusu, N. Takeshita, J. Yamaura, Y. Okamoto and Z. Hiroi

Physica C 470, S738–S739 (2010).

Superconducting and Structural Transitions in the b-Pyrochlore Oxide KOs2O6 under High Pressure

H. Ogusu, N. Takeshita, K. Izawa, J. Yamaura, Y. Ohishi, S. Tsutsui, Y. Okamoto and Z. Hiroi

Journal of the Physical Society of Japan 79, 114710 (2010).

Rattling motion in β-pyrochlore compounds explored by the millimeter-wave conductivity measurement

A. Maeda, K. Oba, Y. Imai, J.-i. Yamaura and Z. Hiroi

Physica C 207, S699–S700 (2010).

Orbital order and partial electronic delocalization in a triangular magnetic metal Ag_{2}MnO_{2}

S. Ji, E. J. Kan, M. H. Whangbo, J. H. Kim, Y. Qiu, M. Matsuda, H. Yoshida, Z. Hiroi, M. A. Green, T. Ziman and S. H. Lee

Physical Review B 81(9), 094421 (2010).

Low temperature specific heat of the β-pyrochlore superconductors under high pressure

T. Isono, D. Iguchi, Y. Machida, K. Izawa, B. Salce, J. Flouquet, H. Ogusu, J. Yamaura and Z. Hiroi

Physica C 470, S721–S722 (2010).

Metallic and superconducting materials with frustrated lattices.

Z. Hiroi and M. Ogata (2010). Introduction to Frustrated Magnetism. C. Lacroix, P. Mendels and F. Mila, Springer: 587-627.

Lattice dynamical study of alkaline atom vibrations with anharmonic interactions in [beta]-pyrochlore oxides

T. Hasegawa, N. Ogita, Y. Nagao, J.-I. Yamaura, Z. Hiroi and M. Udagawa

Physica C: Superconductivity 470(Supplement 1), S695-S696 (2010).

Lattice dynamical study of alkaline atom vibrations with anharmonic interactions in β-pyrochlore oxides

T. Hasegawa, N. Ogita, Y. Nagao, J. Yamaura, Z. Hiroi and M. Udagawa

Physica C 207, S695–S696 (2010).

Resonant Photoemission Spectroscopy of Layered Triangular Lattices

Ag2MO2 (M = Ni and Mn); Evidence for M 3d States at Fermi Level

R. Eguchi, H. Yoshida, Y. Okamoto, A. Chainani, M. Matsunami, Y. Ishida, M. Oura, Y. Senba, H. Ohashi, S. Shin and Z. Hiroi

J. Phys. Soc. Jpn. 79(2), 023704 (2010).

2009

Phase Diagram and Spin Dynamics in Volborthite with a Distorted Kagome Lattice

M. Yoshida, M. Takigawa, H. Yoshida, Y. Okamoto and Z. Hiroi

Physical Review Letters 103(7), 077207 (2009).

Magnetization "steps" in spin liquids on the kagome lattice

H. Yoshida, Y. Okamoto, T. Tayama, T. Sakakibara, M. Tokunaga, A. Matsuo, Y. Narumi, K. Kindo, M. Yoshida, M. Takigawa and Z. Hiroi

J. Phys. Soc. Jpn. 78(4), 043704 (2009).

Re-examination of the crystal structure of the ß-pyrochlore oxide superconductor KOs2O6 by X-ray and convergent-beam electron diffraction analyses

J. Yamaura, Z. Hiroi, K. Tsuda, K. Izawa, Y. Ohishi and S. Tsutsui

Solid State Commun. 149(1-2), 31-34 (2009).

Sudden disappearance of the first-order transition in ß-pyrochlore KOs2O6 under low pressure

K. Umeo, H. Kubo, J. Yamaura, Z. Hiroi and T. Takabatake

J. Phys. Soc. Jpn 78(12), 123602 (2009).

Superconducting weak link generated on a linear array of substrate steps in ultrathin films of YBa2 Cu3 O7- delta

A. Tsurumaki and Z. Hiroi

Physical Review B 80(22), 220505 (2009).

Effect of UV light irradiation in SnO2 thin film

N. Takubo, Y. Muraoka and Z. Hiroi

Journal of Physics: Conference Series 148, 012025 (2009).

Conductivity switching by ultraviolet light in SnO2 thin films

N. Takubo, Y. Muraoka and Z. Hiroi

Appl. Phys. Express 2(4), 045501 (2009).

Static magnetic order in metallic triangular antiferromagnet Ag2MnO2

J. Sugiyama, H. Nozaki, Y. Ikedo, K. Mukai, P. L. Russo, D. Andreica, A. Amato, H. Yoshida and Z. Hiroi

Physica B 404, 777-780 (2009).

Vesignieite BaCu3V2O8(OH)2 as a Candidate Spin-1/2 Kagome Antiferromagnet

Y. Okamoto, H. Yoshida and Z. Hiroi

J. Phys. Soc. Jpn. 78(3), 033701 (2009).

S = 1/2 kagome lattice antiferromagnet Cu3V2O7(OH)2 · 2H2O studied by high field ESR

H. Ohta, W. Zhang, S. Okubo, M. Tomoo, M. Fujisawa, H. Yoshida, Y. Okamoto and Z. Hiroi

J. Phys.: Conf. Series 145, 012010 (2009).

Study of photo-induced phenomena in VO2 by terahertz pump-probe spectroscopy

M. Nakajima, N. Takubo, Z. Hiroi, Y. Ueda and T. Suemoto

Journal of Luminescence 129(12), 1802-1805 (2009).

JPSJ Editors' Choice

Rattling-induced superconductivity in the beta-pyrochlore oxides AOs2O6:
Y. Nagao, J. Yamaura, H. Ogusu, Y. Okamoto, and Z. Hiroi, J. Phys. Soc. Jpn, 78(6), 064702, 2009.

Photo-induced conductivity in tin dioxide thin films
Y. Muraoka, N. Takubo, and Z. Hiroi; J. Appl. Phys. 105, 103702, 2009.

Magnetization "steps" in spin liquids on the kagome lattice:
H. Yoshida, Y. Okamoto, T. Tayama, T. Sakakibara, M. Tokunaga, A. Matsuo, Y. Narumi, K. Kindo, M. Yoshida, M. Takigawa, and Z. Hiroi, J. Phys. Soc. Jpn., 78, 043704, 2009.

JPSJ Editors' Choice & Open Select
Vesignieite BaCu3V2O8(OH)2 as a Candidate Spin-1/2 Kagome Antiferromagnet:
Y. Okamoto, H. Yoshida, and Z. Hiroi, J. Phys. Soc. Jpn., 78, 033701, 2009.

Structure and photoemission spectroscopy of strain-controlled metal-insulator transition in NdNiO[sub 3] thin films
R. Eguchi, Y. Okamoto, Z. Hiroi, S. Shin, A. Chainani, Y. Tanaka, M. Matsunami, Y. Takata, Y. Nishino, K. Tamasaku, M. Yabashi, and T. Ishikawa; J. Appl. Phys. 105, 056103-056103, 2009.

Conductivity switching by ultraviolet light in SnO2 thin films
N. Takubo, Y. Muraoka, and Z. Hiroi; Appl. Phys. Express 2, 045501, 2009.

Effect of UV light irradiation in SnO2 thin film
N. Takubo, Y. Muraoka, and Z. Hiroi; J. Phys.: Conf. Series 148, 012025, 2009.

Spin-1/2 kagome compounds: volborthite vs herbertsmithite:
Z. Hiroi, H. Yoshida, Y. Okamoto, and M. Takigawa, J. Phys.: Conf. Series, 145, 012002, 2009.

S = 1/2 kagome lattice antiferromagnet Cu3V2O7(OH)2 ･2H2O studied by high field ESR:
H. Ohta, W. Zhang, S. Okubo, M. Tomoo, M. Fujisawa, H. Yoshida, Y. Okamoto, and Z. Hiroi, J. Phys.: Conf. Series, 145, 012010, 2009.

Re-examination of the crystal structure of the [beta]-pyrochlore oxide superconductor KOs2O6 by X-ray and convergent-beam electron diffraction analyses:
J. Yamaura, Z. Hiroi, K. Tsuda, K. Izawa, Y. Ohishi, and S. Tsutsui, Solid State Commun., 149, 31-34, 2009.

2008

Static magnetic order in metallic triangular antiferromagnet Ag2MnO2 detected by muon-spin spectroscopy:
J. Sugiyama, H. Nozaki, Y. Ikedo, K. Mukai, P. L. Russo, D. Andreica, A. Amato, H. Yoshida, and Z. Hiroi, Phys. Rev. B, 78, 104427, 2008.

Raman scattering in KOs2O6:
T. Hasegawa, Y. Takasu, N. Ogita, M. Udagawa, J. Yamaura, Y. Nagao, and Z. Hiroi, Phys. Rev. B, 77, 064303, 2008.

Photoinduced metallic state in VO2 proved by the terahertz pump-probe spectroscopy:
M. Nakajima, N. Takubo, Z. Hiroi, Y. Ueda, and T. Suemoto, Appl. Phys. Lett., 92, 011907, 2008.

Fermi surface in the superconducting beta-pyrochlore oxide CsOs2O6:
T. Terashima, S. Uji, Y. Nagao, J. Yamaura, Z. Hiroi, and H. Harima, Phys. Rev. B, 77, 064509, 2008.

Temperature-dependent Raman scattering studies of the geometrically frustrated pyrochlores Dy2Ti2O7, Gd2Ti2O7 and Er2Ti2O7:
M. Maczka, J. Hanuza, K. Hermanowicz, A. F. Fuentes, K. Matsuhira, and Z. Hiroi, Journal of Raman Spectroscopy, 39, 537-544, 2008.

Full-gap superconductivity with strong electron correlations in the beta-pyrochlore KOs2O6:
Y. Kasahara, Y. Shimono, T. Kato, K. Hashimoto, T. Shibauchi, Y. Matsuda, S. Yonezawa, Y. Muraoka, J. Yamaura, Y. Nagao, and Z. Hiroi, Phys. B: Condens. Matter, 403, 1068-1070, 2008.

Synthesis and structure of b-pyrochlore oxide superconductors CsOs2O6 abd RbOs2O6:
S. Yonezawa, T. Kakiuchi, H. Sawa, J. Yamaura, Y. Muraoka, F. Sakai, and Z. Hiroi, in preparation, 2008.

Photoemission evidence for a Mott-Hubbard metal-insulator transition in VO2:
R. Eguchi, M. Taguchi, M. Matsunami, K. Horiba, K. Yamamoto, Y. Ishida, A. Chainani, Y. Takata, M. Yabashi, D. Miwa, Y. Nishino, K. Tamasaku, T. Ishikawa, Y. Senba, H. Ohashi, Y. Muraoka, Z. Hiroi, and S. Shin, Phys. Rev. B, 78, 075115, 2008.

Generalized density-of-states and anharmonicity of the low-energy phonon bands from coherent inelastic neutron scattering response in the pyrochlore osmates AOs[sub 2]O[sub 6] (A = K, Rb, Cs):
H. Mutka, M. M. Koza, M. R. Johnson, Z. Hiroi, J. Yamaura, and Y. Nagao, Phys. Rev. B, 78, 104307-104307, 2008.

Neutron diffraction study of layered Ni dioxides: Ag2NiO2:
H. Nozaki, J. Sugiyama, M. Janoschek, B. Roessli, V. Pomjakushin, L. Keller, H. Yoshida, and Z. Hiroi, J. Phys.: Condens. Matter, 20, 104236, 2008.

Unique phase transition on spin-2 triangular lattice of Ag2MnO2:
H. Yoshida, S. Ahlert, M. Jansen, Y. Okamoto, J. Yamaura, and Z. Hiroi, J. Phys. Soc. Jpn, 77, 074719, 2008.

2007
Precise control of band filling in NaxCoO2:
D. Yoshizumi, Y. Muraoka, Y. Okamoto, Y. Kikuchi, J.-I. Yamaura, M. Mochizuki, M. Ogata, and Z. Hiroi, J. Phys. Soc. Jpn., 76, 063705, 2007.

NMR observation of rattling phonons in the pyrochlore superconductor KOs2O6:
M. Yoshida, K. Arai, R. Kaido, M. Takigawa, S. Yonezawa, Y. Muraoka, and Z. Hiroi, Phys. Rev. Lett., 98, 197002, 2007.

Impurity effects on the Ni3+ triangular lattice of Ag2NiO2:
H. Yoshida, Y. Muraoka, and Z. Hiroi, J. Phys.: Condens. Matter, 19, 145235, 2007.

Effects of Rattling Phonons on Quasiparticle Excitation and Dynamics in the Superconducting beta-Pyrochlore KOs2O6 Superconductor:
Y. Shimono, T. Shibauchi, Y. Kasahara, T. Kato, K. Hashimoto, Y. Matsuda, J. Yamaura, Y. Nagao, and Z. Hiroi, Phys. Rev. Lett., 98, 257004, 2007.

Interplay of superconductivity and rattling phenomena in beta-pyrochlore KOs2O6 stuided by photoemission spectroscopy:
T. Shimojima, Y. Shibata, K. Ishizaka, T. Kiss, T. Togashi, S. Watanabe, J. Yamaura, S. Yonezawa, Y. Muraoka, Z. Hiroi, T. Saitoh, and S. Shin, Phys. Rev. Lett., 99, 117003, 2007.

Neutron-Scattering Study of the Localized Mode in beta-Pyrochlore Superconductors AOs2O6:
K. Sasai, K. Hirota, Y. Nagao, S. Yonezawa, and Z. Hiroi, J. Phys. Soc. Jpn., 76, 104603, 2007.

Crystalline Electric Field Effect and Magnetic Properties of CeRhSi3 Single Crystal:
Y. Muro, M. Ishikawa, K. Hirota, Z. Hiroi, N. Takeda, N. Kimura, and H. Aoki, J. Phys. Soc. Jpn., 76, 33706, 2007.

Uniaxial pressure effects on spin-icecompound Dy2Ti2O7:
M. Mito, S. Kuwabara, K. Matsuhira, H. Deguchi, S. Takagi, and Z. Hiroi, J. Mag. Mag. Mat., 310, e432-e434, 2007.

Antiferroquadrupolar Ordering and Anisotropic Magnetic Phase Diagram of Dysprosium Palladium Bronze, DyPd3S4:
E. Matsuoka, T. Tayama, T. Sakakibara, Z. Hiroi, N. Shirakawa, N. Takeda, and M. Ishikawa, J. Phys. Soc. Jpn., 76, 084717, 2007.

Photoemission study of TiO2/VO2 interfaces:
K. Maekawa, M. Takizawa, H. Wadati, T. Yoshida, A. Fujimori, H. Kumigashira, M. Oshima, Y. Muraoka, Y. Nagao, and Z. Hiroi, Phys. Rev. B, 76, 115121, 2007.

Anomalous Magnetic Phase in an Undistorted Pyrochlore Oxide Cd2Os2O7 Induced by Geometrical Frustration:
A. Koda, R. Kadono, K. Ohishi, S. R. Saha, W. Higemoto, S. Yonezawa, Y. Muraoka, and Z. Hiroi, J. Phys. Soc. Jpn., 76, 063703, 2007.

Bose-Einstein Condensation of Quasi Two-Dimensional Frustrated
Quantum Magnet (CuCl)LaNb2O7:
A. Kitada, Z. Hiroi, Y. Tsujimoto, T. Kitano, H. Kageyama, Y. Ajiro, and K. Yoshimura, J. Phys. Soc. Jpn., 76, 093706, 2007.

A second phase transition and superconductivity in the ?-pyrochlore oxide KOs2O6:
Z. Hiroi, S. Yonezawa, and J. Yamaura, J. Phys.: Condens. Matter, 19, 145283, 2007.

Extremely strong-coupling superconductivity and anomalous lattice properties in the ?-pyrochlore oxide KOs2O6:
Z. Hiroi, S. Yonezawa, Y. Nagao, and J. Yamaura, Phys. Rev. B, 76, 014523, 2007.

Chemical trends of superconducting properties in pyrochlore oxides:
Z. Hiroi, J. Yamaura, S. Yonezawa, and H. Harima, Physica C, 460-462, 20-27, 2007.

Electronic structure of VO2/TiO2: Nb upon photocarrier injection:
R. Eguchi, S. Tsuda, T. Kiss, A. Chainani, Y. Muraoka, Z. Hiroi, and S. Shin, Phys. Rev. B, 75, 073102, 2007.

Isotropically Gapped Strong-Coupling Superconductivity in the beta-Pyrochlore KOs2O6:
Evidence from Penetration Depth Measurements:
I. Bonalde, R. Ribeiro, W. Bramer-Escamilla, J. Yamaura, Y. Nagao, and Z. Hiroi, Phys. Rev. Lett., 98, 227003, 2007.

2006

Upper critical field of beta-pyrochlore KOs2O6 single crystals, E. Ohmichi, T. Osada, S. Yonezawa, Y. Muraoka, and Z. Hiroi, J. Phys. Soc. Jpn. 75, 045002, 2006.

Anomalous flux pinning in beta-pyrochlore oxide superconductor KOs2O6, Z. Hiroi and S. Yonezawa, J. Phys. Soc. Jpn. 75, 043701, 2006.

Spin-1/2 triangular lattice with orbital degeneracy in a metallic oxide Ag2NiO2, H. Yoshida, Y. Muraoka, T. Soegel, M. Jansen, and Z. Hiroi, Phys. Rev. B 73, 020408, 2006.

Thermal Conductivity of the Pyrochlore Superconductor KOs2O6: Strong Electron Correlations and Fully Gapped Superconductivity, Y. Kasahara, Y. Shimono, T. Shibauchi, Y. Matsuda, S. Yonezawa, Y. Muraoka, and Z. Hiroi, Phys. Rev. Lett. 96, 247004, 2006.

Ferromagnetic ordering on the triangular lattice in the pyrochlore spin-ice compound Dy2Ti2O7, H. Sato, K. Matsuhira, T. Tayama, Z. Hiroi, S. Takagi, and T. Sakakibara, J. Phys.: Condens. Matter 18, L297-L303, 2006.

Specific heat of YFe3(BO3)4, Y0.5Gd0.5Fe3(BO3)4, and GdFe3(BO3)4, A. N. Vasiliev, E. A. Popova, L. N. Bezmaternykh, V. L. Temerov, and Z. Hiroi, J. Exp. Theoret. Phys. 102, 262-265, 2006.

Role of electron-electron and electron-phonon interaction effects in the optical conductivity of VO2, K. Okazaki, S. Sugai, Y. Muraoka, and Z. Hiroi, Phys. Rev. B 73, 165116, 2006.

Incommensurate magnetic order in Ag2NiO2 studied with muon-spin-rotation and relaxation spectroscopy, J. Sugiyama, Y. Ikedo, K. Mukai, J. H. Brewer, E. J. Ansaldo, G. D. Morris, K. H. Chow, H. Yoshida, and Z. Hiroi, Phys. Rev. B 73, 224437, 2006.

NMR studies of beta-pyrochlore superconductors with osmium, under hydrostatic pressure, K. Arai, M. Takigawa, S. Yonezawa, Y. Muraoka, and Z. Hiroi, Physica B 378-80, 878-879, 2006.

Uncommonly high upper critical field of the pyrochlore superconductor KOs2O6 below the enhanced paramagnetic limit, T. Shibauchi, L. Krusin-Elbaum, Y. Kasahara, Y. Shimono, Y. Matsuda, R. McDonald, C. H. Mielke, S. Yonezawa, Z. Hiroi, M. Arai, T. Kita, G. Blatter, and M. Sigrist, Phys. Rev. B 74, 220506(R), 2006.

Kagome Ice State in the Dipolar Spin Ice Dy2Ti2O7, Y. Tabata, H. Kadowaki, K. Matsuhira, Z. Hiroi, N. Aso, E. Ressouche, and B. Fak, Phys. Rev. Lett. 97, 257205, 2006.

Spin-1/2 triangular lattice with orbital degeneracy in a metallic oxide Ag2NiO2:
H. Yoshida, Y. Muraoka, T. Soegel, M. Jansen and Z. Hiroi; Phys. Rev. B73 (2006) 020408.

PPMS磁場騒動顛末記　(in Japanese) 広井善二:　固体物理 41(3) 229-233 (2006).

Anomalous Flux Pinning in β-Pyrochlore Oxide Superconductor KOs2O6:
Zenji Hiroi and Shigeki Yonezawa; JPSJ 75(4) (2006) 043701.

2005

Erratum to Three Papers on the β-Pyrochlore Oxide Superconductors:
JPSJ 74(12) (2005) 3400.

Retraction: "Unprecedented Superconductivity in β-Pyrochlore Osmate KOs2O6":
JPSJ 75(12) (2005) 3399.

Crystal structure of the pyrochlore oxide superconductor KOs2O6J. Yamaura, S. Yonezawa, Y. Muraoka and Z. Hiroi; J. Solid State Chem. 179 (2005) 334.

Photocarrier Injection and Current-Voltage Characteristics of a La0.8Sr0.2MnO3/SrTiO3:Nb Heterojunction at Low Temperature: T. Muramatsu, Y. Muraoka and Z. Hiroi, Jpn. J. Appl. Phys. 44, 7367-7371 (2005).

新しいパイロクロア型オスミウム酸化物超伝導体　(in Japanese) 広井善二:　固体物理 40(2) 43-50 (2005).

Anomalous pressure dependence of the superconducting transition temperature of β-pyrochlore AOs2O6 oxides : T. Muramatsu, N. Takeshita, C. Terakura, H. Takagi, Y. Tokura, S. Yonezawa, Y. Muraoka and Z. Hiroi, Phys. Rev. Lett. 95, 167004 (2005).

39K and 87Rb Nuclear Magnetic Resonance in the Pyrochlore Superconductors AOs2O6 (A=K, Rb): K. Arai, J. Kikuchi, K. Kodama, M. Takigawa, S. Yonezawa, Y. Muraoka, Z. Hiroi, submitted to Phys. Rev. Lett. ; cond-mat/0411460.

Second Anomaly in the Specific Heat of β-Pyrochlore Oxide Superconductor KOs2O6: Zenji Hiroi, Shigeki Yonezawa, Jun-Ichi Yamaura, Takaki Muramatsu, and Yuji Muraoka, J. Phys. Soc. Jpn, 74(6), 1682-1685 (2005).

Possible Anisotropic Order Parameter in Pyrochlore Superconductor KOs2O6 Probed by Muon Spin Rotation
A. Koda, W. Higemoto, K. Ohishi, S. R. Saha, and R. Kadono, S. Yonezawa, Y. Muraoka, and Z. Hiroi
J. Phys. Soc. Jpn., 74(6), 1678-1681 (2005).

Specific Heat of the β-Pyrochlore Oxide Superconductors  CsOs2O6 and RbOs2O6: Zenji Hiroi, Shigeki Yonezawa, Takaki Muramatsu, Jun-Ichi Yamaura, and Yuji Muraoka, J. Phys. Soc. Jpn: 74(4) (2005) 1255-1262.

2004

遷移金属酸化物ヘテロ接合における光キャリア注入　(in Japanese)
広井善二、村岡祐治、村松孝樹、山内　徹、山浦淳一: 固体物理 39(4) 211-224 (2004).

スピンアイスの磁場下における巨視的縮退と液相ー気相型相転移　(in Japanese)
松平和之、広井善二、榊原俊郎: 日本物理学会誌 59(7) 460-464 (2004).

Photoemission Study of YBa2Cu3Oy Thin Films under Light Illumination: D. Asakura, J. W. Quilty, K. Takubo, S. Hirata, T. Mizokawa, Y. Muraoka and Z. Hiroi, Phys. Rev. Lett. 93 (2004) 247006.

Photogenerated hole carrier injection to YBa2Cu3O7-x in an oxide heterostructure: Y. Muraoka, T. Muramatsu, J. Yamaura and Z. Hiroi, Appl. Phys. Lett., 2004. 85(14): p. 2950-2952.

High pressure effects on superconductivity in the β-pyrochlore oxides AOs2O6 (A = K, Rb, Cs): Takaki Muramatsu, Shigeki Yonezawa, Yuji Muraoka and Zenji Hiroi, J. Phys. Soc. Jpn: 73(10) (2004) 2912-2913.

Photocarrier injection and the I-V characteristics of La0.8Sr0.2MnO3/SrTiO3:Nb heterojunctions
Takaki Muramatsu, Yuji Muraoka, Zenji Hiroi
cond-mat/040; submitted to SSC

New β-Pyrochlore Oxide Superconductor CsOs2O6
Shigeki Yonezawa, Yuji Muraoka and Zenji Hiroi
J. Phys. Soc. Jpn: 73(7) (2004) 1655-1656.

New Pyrochlore Oxide Superconductor RbOs2O6
Shigeki YONEZAWA ,Yuji MURAOKA,Yoshitaka MATSUSHITA and Zenji HIROI
J. Phys. Soc. Jpn: 73(4) (2004) 819-821

Superconductivity in a pyrochlore-related oxide KOs2O6
S. Yonezawa, Y. Muraoka, Y. Matsushita and Z. Hiroi:
J. Phys.: Condens. Matter 16 (2004) L9-L12.

2003

和文解説：パイロクロア酸化物超伝導体Cd2Re2O7　(in Japanese)
広井善二:応用物理, 72, 1 (2003) 47-49.

Efficiency of photocarrier injection in a VO2/TiO2:Nb heterostructure
Z. Hiroi, T. Yamauchi, Y. Muraoka, T. Muramatsu and J. Yamaura:
J. Phys. Soc. Jpn, 72(12) (2003) 3049-3052.

Ferromagnetic Ising Spin Chains Emerging from the Spin Ice under Magnetic Field
Zenji HIROI, Kazuyuki MATSUHIRA and Masao OGATA:
J. Phys. Soc. Jpn. 72(12) (2003) 3045-3048.

Efficient Photocarrier Injection to Transition Metal Oxides
Y. Muraoka, T. Yamauchi, T. Muramatsu, J. Yamaura and Z. Hiroi:
J. Mag. Mag. Mat. 272-276 (2004) 448-449; Proc. of ICM2003.

Photocarrier Injection to Perovskite Manganites
T. Muramatsu, Y. Muraoka, T. Yamauchi, J. Yamaura and Z. Hiroi:
J. Mag. Mag. Mat. 272-276 (2004) E297-E298; Proc. of ICM2003.

2 K superconductivity in pyrochlore oxide Cd2Re2O7
Z. Hiroi and M. Hanawa:
Physica B, 329-333 (2003) 1317-1318.

Photocarrier Injection to Transition Metal Oxides
Y. Muraoka and Z. Hiroi:
J. Phys. Soc. Jpn, 72 (2003) 781-784.

Specific Heat of Kagome Ice in the Pyrochlore Oxide Dy2Ti2O7

Zenji Hiroi, Kazuyuki Matsuhira1, Seishi Takagi1, Takashi Tayama and Toshio Sakakibara:
J. Phys. Soc. Jpn. 72 (2003) 411-418.

Correlations and Semimetallic Behaviors in Pyrochlore Oxide Cd2Re2O7
Z. Hiroi, M. Hanawa, Y. Muraoka and H. Harima:
J. Phys. Soc. Jpn., 72 (2003) 21-24.

2002

和文解説：パイロクロア酸化物超伝導体Cd2Re2O7　(in Japanese)
広井善二、瀧川　仁: 固体物理, 37, 4 (2002) 253-364.

Efficient photocarrier injection in a transition metal oxide heterostructure
Y. Muraoka, T. Yamauchi, Y. Ueda and Z. Hiroi:
J. Phys.: Condens. Matter, 14 (2002) L757-L763.

Exact result of ground-state entropy for Ising pyrochlore magnets under a magnetic field along [111] axis

M. Udagawa, M. Ogata, Z. Hiroi, J. Phys. Soc. Jpn 71 (2002) 2365.

A new macroscopically degenerate ground state in the spin ice compound Dy2Ti2O7 under a magnetic field
K. Matsuhira, Z. Hiroi, T. Tayama, S. Takagi and T. Sakakibara:
J. Phys.: Condens. Matter, 14 (2002) L559-L565.

Metal-insulator transition of VO2 thin films grown on TiO2 (001) and (110) substrates
Y. Muraoka and Z. Hiroi:
Appl. Phys. Lett., 80, 4 (2002) 583-585.

Low Temperature Symmetry of Pyrochlore Oxide Cd2Re2O7
J. Yamaura and Z. Hiroi:
J. Phys. Soc. Jpn. 71 (2002) 2598.

Superconducting properties of the pyrochlore oxide Cd2Re2O7
Z. Hiroi and M. Hanawa:
J. Phys. Chem. Solids, 63, 6-8 (2002) 1021-1026.

Structural phase transition in the superconducting pyrochlore oxide Cd2Re2O7
M. Hanawa, J. Yamaura, Y. Muraoka, F. Sakai and Z. Hiroi:
J. Phys. Chem. Solids, 63, 6-8 (2002) 1027-1030.

Cd and Re NMR/NQR in pyrochlore compound Cd2Re2O7
O. Vyaselev, K. Kobayashi, K. Arai, J. Yamazaki, K. Kodama, M. Takigawa, M. Hanawa and Z. Hiroi:
J. Phys. Chem. Solids, 63, 6-8 (2002) 1031-1034.

Quasiparticle excitation in the superconducting pyrochlore Cd2Re2O7 probed by Muon Spin Rotation
R. Kadono, W. Higemoto, A. Koda, Y. Kawasaki, M. Hanawa and Z. Hiroi:
J. Phys. Soc. Jpn, 71, 3 (2002) 709-712.

Second phase transition in pyrochlore oxide Cd2Re2O7
Z. Hiroi, J. Yamaura, Y. Muraoka and M. Hanawa:
J. Phys. Soc. Jpn, 71, 7 (2002) 1634-1636.

High-pressure study on the superconducting pyrochlore oxide Cd2Re2O7
Z. Hiroi, T. Yamauchi, T. Yamada, M. Hanawa, Y. Ohishi, O. Shimomura, M. Abliz, M. Hedo and Y. Uwatoko:
J. Phys. Soc. Jpn., 71, 6 (2002) 1553-1557.

Sructural, magnetic, and superconducting properties of Cd2Re2O7: Cd NMR and Re NQR
O. Vyaselev, K. Arai, K. Kobayashi, J. Yamazaki, K. Kodama, M. Takigawa, M. Hanawa and Z. Hiroi:
Phys. Rev. Lett., 89, 1 (2002) 017001-1.

2001年

和文解説：超伝導になったパイロクロア酸化物　(in Japanese)
広井善二: パリティー, 16, 11 (2001) 32-35.

Spin-1/2 quantum antiferromagnetic chains with adjustable superexchange interactions found in BaCu2(Si1-xGex)2O7
T. Yamada, M. Takano and Z. Hiroi:
J. Alloys and Compounds, 317-318 (2001) 171-176.

S=1/2 antiferromagnetic chains and dimers on hole-doped edge-sharing CuO2 chains
Z. Hiroi, M. Okumura, T. Yamada and M. Takano:
J. Alloys and Compounds, 317-318 (2001) 164-170.

Spin-1/2 kagome-like lattice in Volborthite Cu3V2O7(OH)2/2H2O
Z. Hiroi, N. Kobayashi, M. Hanawa, M. Nohara, H. Takagi, Y. Kato and M. Takigawa:
J. Phys. Soc. Jpn, 70, 11 (2001) 1-8.

Spin-1/2 quantum antiferromagnetic chains with tunable superexchange interactions found in BaCu2(Si1-xGex)2O7
T. Yamada, Z. Hiroi and M. Takano:
J. Solid State Chem., 156, 1 (2001) 101-109.

Superconductivity at 1 K in Cd2Re2O7
M. Hanawa, Y. Muraoka, T. Tayama, T. Sakakibara, J. Yamaura and Z. Hiroi:
Phys. Rev. Lett., 87, 18 (2001) 187001.

High-Field ESR Study of Kagome-Like Substance Cu3V2O7(OH)22H2O
S. Okubo, H. Ohta, K. Hazuki, T. Sakurai, N. Kobayashi and Z. Hiroi:
Physica B, 294-295 (2001) 75-78.

2000年

Submillimeter-wave ESR measurements of Ca1-xCuO2 (x = 0.164) with edge-sharing CuO2 chains
A. Ueda, H. Ohta, S. Okubo, Z. Hiroi, M. Okumura and M. Takano:
Appl. Magn. Reson., 19 (2000) 399-402.

Coexistence of S = 1/2 antiferromagnetic chains and dimers on hole-doped CuO2 chains in Ca1-xCuO2
Z. Hiroi, M. Okumura, T. Yamada and M. Takano:
J. Phys. Soc. Jpn, 69, 6 (2000) 1824-1833.

Spin-1/2 Heisenberg antiferromagnetic chains in the frustrated spinel lattice of GeCu2O4
T. Yamada, Z. Hiroi, M. Takano, M. Nohara and H. Takagi:
J. Phys. Soc. Jpn, 69, 5 (2000) 1477-1483.

Appearance of magnetic long-range order in the spin-ladder compound La1-xSrxCuO2.5
K. Ishii, A. Yamashita, K. Ohishi, J. Akimitsu, R. Kadono, N. Kobayashi, M. Takano and Z. Hiroi:
Physica B, 289-290 (2000) 165-167.