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Journal Articles

Growth of PrFeAsO $_{1-y}$ single crystals and its characterization

Ishikado, Motoyuki; Shamoto, Shinichi; Kito, Hijiri*; Iyo, Akira*; Eisaki, Hiroshi*; Ito, Toshimitsu*; Tomioka, Yasuhide*

Physica C, 470(Suppl.1), p.S322 - S323, 2010/12

https://doi.org/10.1016/j.physc.2009.11.165

Times Cited Count：3 Percentile：17.17(Physics, Applied)

Single crystals of oxygen deficient oxypnictide superconductor PrFeAsO $_{1-y}$ have been grown by using belt-type anvil high pressure synthesis apparatus. Superconducting transition temperature ( $textit{T$_c$}$ ) of the obtained single crystal is 45 K, and typical size is about 800 1000 30 . In-plane electrical resistivity shows almost proportional to temperature as well as the copper oxide high temperature superconductors, suggesting the existence of effects of strong inelastic scattering like copper oxide high temperature superconductor. In addition, we obtained non-superconducting parent single crystal by annealing the as-grown single crystal under ambient pressure. Resistivity of parent single crystal is characterized by the kink near 150 K corresponding to the structural transition, and the structure near 12 K, which is thought to be originating from the magnetic order of Pr ion.

Journal Articles

Strong carrier-scattering in iron-pnictide superconductors FeAsO $_{1-y}$ ( = La and Nd) obtained from charge transport experiments

Ishida, Shigeyuki*; Nakajima, Masamichi*; Tomioka, Yasuhide*; Ito, Toshimitsu*; Miyazawa, Kiichi*; Kito, Hijiri*; Lee, C.-H.*; Ishikado, Motoyuki; Shamoto, Shinichi; Iyo, Akira*; et al.

Physical Review B, 81(9), p.094515_1 - 094515_6, 2010/03

https://doi.org/10.1103/PhysRevB.81.094515

Times Cited Count：21 Percentile：64.67(Materials Science, Multidisciplinary)

Characteristic normal-state charge transport is found in the oxygen-deficient iron-arsenides FeAsO $_{1-y}$ (: La and Nd) with the highest $_{c}$ 's among known Fe-based superconductors. The effect of "doping" in this system is mainly on the carrier scattering, quite distinct from that in high- $_{c}$ cuprates. In the superconducting regime of the La system with maximum $_{c}$ = 28 K, the low-temperature resistivity is dominated by a $^{2}$ term. On the other hand, in the Nd system with $_{c}$ higher than 40 K, the carriers are subject to stronger scattering showing -linear resistivity and small magnetoresistance. Such strong scattering appears crucial for high- $_{c}$ superconductivity in the iron-based system.

Journal Articles

Muon spin rotation measurements of heterogeneous field response in overdoped La $_{2-x}$ Sr $_{x}$ CuO $_{4}$

MacDougall, G. J.*; Savici, A. T.*; Aczel, A. A.*; Birgeneau, R. J.*; Kim, H.*; Kim, S.-J.*; Ito, Toshimitsu*; Rodriguez, J. A.*; Russo, P. L.*; Uemura, Yasutomo*; et al.

Physical Review B, 81(1), p.014508_1 - 014508_7, 2010/01

https://doi.org/10.1103/PhysRevB.81.014508

Times Cited Count：11 Percentile：46.11(Materials Science, Multidisciplinary)

Journal Articles

Growth of single crystal PrFeAsO $_{1-y}$ and its characterization

Ishikado, Motoyuki; Shamoto, Shinichi; Kito, Hijiri*; Iyo, Akira*; Eisaki, Hiroshi*; Ito, Toshimitsu*; Tomioka, Yasuhide*

Physica C, 469(15-20), p.901 - 904, 2009/10

https://doi.org/10.1016/j.physc.2009.05.094

Times Cited Count：23 Percentile：66.35(Physics, Applied)

We have successfully grown single crystals of oxygen deficient oxypnictide superconductor PrFeAsO $_{1-y}$ by belt-type anvil apparatus using high pressure synthesis method.

Journal Articles

High-pressure synthesis and physical properties of new iron (nickel)-based superconductors

Shirage, P. M.*; Miyazawa, Kiichi*; Ishikado, Motoyuki; Kiho, Kunihiro*; Lee, C.-H.*; Takeshita, Nao*; Matsuhata, Hirofumi*; Kumai, Reiji*; Tomioka, Yasuhide*; Ito, Toshimitsu*; et al.

Physica C, 469(9-12), p.355 - 369, 2009/06

https://doi.org/10.1016/j.physc.2009.03.027

Times Cited Count：40 Percentile：79.94(Physics, Applied)

We have utilized a high-pressure (HP) technique to synthesize a series of newly-discovered iron (nickel)-based superconductors. The effect of (O)-deficiency, variation of ions, and the external pressure on $_{rm c}$ are examined. All the experimental data indicate strong correlation between the crystal structure and the superconductivity of the oxypnictide superconductors. Upper critical field measurement on single crystalline sample of PrFeAsO $_{1-y}$ shows the superconducting anisotropy of 5, which is smaller than cuprates. We also demonstrate that HP technique is applicable for the so-called "122" systems.

Journal Articles

Absence of broken time-reversal symmetry in the pseudogap state of the high temperature La $_{2-x}$ Sr $_{x}$ CuO $_{4}$ superconductor from muon-spin-relaxation measurements

MacDougall, G. J.*; Aczel, A. A.*; Carlo, J. P.*; Ito, Toshimitsu*; Rodriguez, J.*; Russo, P. L.*; Uemura, Yasutomo*; Wakimoto, Shuichi; Luke, G. M.*

Physical Review Letters, 101(1), p.017001_1 - 017001_4, 2008/07

https://doi.org/10.1103/PhysRevLett.101.017001

Times Cited Count：60 Percentile：88.1(Physics, Multidisciplinary)

We have performed zero-field muon spin rotation measurements on single crystals of La $_{2-x}$ Sr $_{x}$ CuO $_{4}$ to search for spontaneous currents in the pseudo-gap state. By comparing measurements on materials across the phase diagram, we put strict upper limits on any possible time-reversal symmetry breaking fields that could be associated with the pseudo-gap. Comparison between experimental limits and proposed circulating current states effectively eliminates the possibility that such states exist in this family of materials.

Journal Articles

Effects of hole doping on magnetic ground and excited states in the edge-sharing CuO chains of Ca $_{2+x}$ Y $_{2-x}$ CuO $_{10}$

Matsuda, Masaaki; Kakurai, Kazuhisa; Kurogi, Shogo*; Kudo, Kazutaka*; Koike, Yoji*; Yamaguchi, Hirotaka*; Ito, Toshimitsu*; Oka, Kunihiko*

Physical Review B, 71(10), p.104414_1 - 104414_8, 2005/03

https://doi.org/10.1103/PhysRevB.71.104414

Times Cited Count：13 Percentile：49.98(Materials Science, Multidisciplinary)

no abstracts in English

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

Magnetic excitations from the edge-sharing CuO $_{2}$ chains in Ca $_{2}$ Y $_{2}$ Cu $_{5}$ O $_{10}$

Matsuda, Masaaki; Yamaguchi, Hirotaka*; Ito, Toshimitsu*; Le, C.*; Oka, Kunihiko*; Mizuno, Yoshiaki*; Toyama, T.*; Maekawa, Sadamichi*; Kakurai, Kazuhisa*

Physical Review B, 63(18), p.180403_1 - 180403_4, 2001/05

https://doi.org/10.1103/PhysRevB.63.180403

Times Cited Count：25 Percentile：75.01(Materials Science, Multidisciplinary)

no abstracts in English

Oral presentation

Inelastic neutron scattering study on Cu $_{3}$ Mo $_{2}$ O $_{9}$

Kuroe, Haruhiko*; Hamasaki, Tomoyuki*; Hase, Masashi*; Kaneko, Koji; Metoki, Naoto; Matsuda, Masaaki; Kakurai, Kazuhisa; Oka, Kunihiko*; Ito, Toshimitsu*; Eisaki, Hiroshi*

no journal, ,

We have measured inelastic neutron scattering in Cu $_{3}$ Mo $_{2}$ O $_{9}$ to study its magnetic-excitation dispersion curves. This material can be treated as a complex of the following two spin subsystems. (1) Quasi-one-dimensional antiferromagnetic (AF) spin chain with the intrachain interaction pJ4 = 6.3 meV, where p is the renormalization factor depending on the system dimension, together with the ferromagnetic and AF interchain interactions -Ja = J 0.01pJ4. (2) AF spin dimers with the interaction J3 = 5.8 meV. The hybridization parameter, representing the intersubsystem interaction between these subsystems, is estimated as Eint sin (k), where Eint = 1.6 meV. The modulation of the molecular field generated by the spin precession in the excited state of the quasi-one-dimensional spin chain plays an important role in this hybridization.

Oral presentation

Growth of single crystal PrFeAsO $_{1-y}$ and its transport properties

Ishikado, Motoyuki; Shamoto, Shinichi; Kito, Hijiri*; Iyo, Akira*; Eisaki, Hiroshi*; Ito, Toshimitsu*; Tomioka, Yasuhide*

no journal, ,

Single crystals of oxygen deficient oxypnictide superconductor PrFeAsO $_{1-y}$ were grown by high pressure method using belt-type anvil apparatus. Grown crystals have shiny ab-plane surfaces. Typical crystal size is about 800100020 mm, which is one order larger than the previous reported LnFeAs(O,F) single crystal size. Upper critical field obtained from resistivity measurement under magnetic field yields anisotropy of 5, which is consistent with other group's reported result. In the session, we will talk details of the method of doping control of the single crystal and doping dependences of anisotropy.

Oral presentation

Growth of single cystal PrFeAsO $_{1-y}$ and transport properties, 2

Ishikado, Motoyuki; Shamoto, Shinichi; Kito, Hijiri*; Iyo, Akira*; Eisaki, Hiroshi*; Ito, Toshimitsu*; Tomioka, Yasuhide*

no journal, ,

In the previous meeting, we have grown single crystals of oxygen deficient oxypnictide high temperature superconductor PrFeAsO $_{1-y}$ , and characterized anisotropy from resistivity under magnetic field. Anisotropy of upper critical field (H $_{c2}$ ) is 5 and is consistent with other group's reported value. In this study, we succeeded to control doping by adjusting the oxygen content. We measured resistivity under magnetic field and estimated anisotropy of the doping controled single crystals, and revealed that anisotropy is not doping dependent. In the session, we report details of doping control, characterization such as resistivity and XRD, estimation of anisotropy.

Oral presentation

Transport properties of PrFeAsO $_{1-y}$

Ishikado, Motoyuki; Shamoto, Shinichi; Kito, Hijiri*; Iyo, Akira*; Eisaki, Hiroshi*; Tomioka, Yasuhide*; Ito, Toshimitsu*

no journal, ,

Since the discovery of iron-based superconductor, extensive research have been done in order to clarify mechanism of superconductivity. But the research have been done mainly on 122 system because of easy availability of single crystal. So far, we have succeeded to grow single crystals of PrFeAsO $_{1-y}$ high-Tc superconductor by high-pressure synthesis method. In the previous talk, we succeeded to control doping by tuning oxygen content of the single crystals, and characterized anisotropy by resistivity measurement under magnetic field. And reported that the anisotropy of iron-based superconductor dose not depend on doping different from cuprates. This time, we measure transport properties, especially for doping dependences of Hall coefficient, and discuss relationship between Hall coefficient and SDW transition on underdoping regime.

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Growth of PrFeAsO $_{1-y}$ single crystals and its characterization

Strong carrier-scattering in iron-pnictide superconductors FeAsO $_{1-y}$ ( = La and Nd) obtained from charge transport experiments

Muon spin rotation measurements of heterogeneous field response in overdoped La $_{2-x}$ Sr $_{x}$ CuO $_{4}$

Growth of single crystal PrFeAsO $_{1-y}$ and its characterization

High-pressure synthesis and physical properties of new iron (nickel)-based superconductors

Absence of broken time-reversal symmetry in the pseudogap state of the high temperature La $_{2-x}$ Sr $_{x}$ CuO $_{4}$ superconductor from muon-spin-relaxation measurements

Effects of hole doping on magnetic ground and excited states in the edge-sharing CuO chains of Ca $_{2+x}$ Y $_{2-x}$ CuO $_{10}$

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

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

Magnetic excitations from the edge-sharing CuO $_{2}$ chains in Ca $_{2}$ Y $_{2}$ Cu $_{5}$ O $_{10}$

Inelastic neutron scattering study on Cu $_{3}$ Mo $_{2}$ O $_{9}$

Growth of single crystal PrFeAsO $_{1-y}$ and its transport properties

Growth of single cystal PrFeAsO $_{1-y}$ and transport properties, 2

Transport properties of PrFeAsO $_{1-y}$