論文 - 辺土　正人

Effect of pressure on the superconductor Cd₂Re₂O₇

Abliz, M; Hedo, M; Uwatoko, Y; Matsumoto, T; Hanawa, M; Hiroi, Z

ACTA PHYSICA POLONICA B   34 ( 2 ) 489 - 492   2003年02月 [ 査読有り ]

掲載種別: 研究論文（学術雑誌）

Charge density wave, superconductivity, and non-metallic behaviour under high pressure in ZrTe3

Igarashi K, Yasuzuka S, Inagaki K, Tanda S, Okajima Y, Hedo M, Uwatoko Y, Yamaya K

JOURNAL DE PHYSIQUE IV   12 ( PR9 ) 97 - 98   2002年11月 [ 査読有り ]

掲載種別: 研究論文（学術雑誌）

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Charge density wave, superconductivity, and non-metallic behaviour under high pressure in ZrTe<inf>3</inf>

K. Igarashi, S. Yasuzuka, K. Inagaki, S. Tanda, Y. Okajima, M. Hedo, Y. Uwatoko, K. Yamaya

Journal De Physique. IV : JP   12 ( 9 )   2002年11月 [ 査読有り ]

掲載種別: 研究論文（国際会議プロシーディングス）

　概要を見る

The charge-density-wave (CDW) order of low-dimensional inorganic conductor ZrTe3 is found to increase with increasing pressure, while the superconductivity with filamentary nature is significantly suppressed. It was evidenced in resistivity measurements under pressure up to 0.8 Gpa. The present results suggest that competition between the superconductivity and the CDW is not simply explained by a nesting effect of the Fermi surface, but other origin is needed. Non-metallic behaviour is also found below 4K under high pressures above 0.6 Gpa. The relationship between the non-metallic state and the pressure-enhanced CDW is expected, although yet inexplicable.

Elucidation of the stable vortex state across the peak effect region in CeRu₂

Tulapurkar, AA; Heidarian, D; Sarkar, S; Ramakrishnan, S; Grover, AK; Yamamoto, E; Haga, Y; Hedo, M; Inada, Y; Onuki, Y

PHYSICA C ( ELSEVIER SCIENCE BV )  355 ( 1-2 ) 59 - 64   2001年06月 [ 査読有り ]

掲載種別: 研究論文（学術雑誌）

　概要を見る

We present magnetization data on a weakly pinned single crystal of CeRu2 showing the existence of a stable state of the vortex matter in the peak effect (PE) region. The stable state is achieved by cycling the magnetic field by a small amplitude. It is characterized by a unique value of the critical current density, independent of the magnetic history of the sample. The results support a recent phenomenological model proposed by Ravikumar et al. [Phys. Rev. B 61 (2000) R6479] which postulates a specific recipe to incorporate the history dependence of the current density. Our data also shows the occurrence of a first order phase transition from an ordered vortex phase to a disordered phase across the PE. (C) 2001 Elsevier Science B.V. All rights reserved.

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Coulomb correlations and two-channel conduction in CuIr2S4 and CuIr2Se4 compounds

Yagasaki K, Nakama T, Hedo M, Burkov AT, Matsumoto N, Nagata S

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS   226   244 - 245   2001年05月 [ 査読有り ]

掲載種別: 研究論文（学術雑誌）

Anomalous resistivity and thermopower of the spinel-type compounds CuIr2S4 and CuIr2Se4

Burkov AT, Nakama T, Hedo M, Shintani K, Yagasaki K, Matsumoto N, Nagata S

PHYSICAL REVIEW B   61 ( 15 ) 10049 - 10056   2000年04月 [ 査読有り ]

掲載種別: 研究論文（学術雑誌）

Anisotropic magnetoresistance in UBe13

Haga Y, Yamamoto E, Honma T, Nakamura A, Hedo M, Araki S, Ohkuni H, Onuki Y

PHYSICA B-CONDENSED MATTER   259-61   627 - 628   1999年01月 [ 査読有り ]

掲載種別: 研究論文（学術雑誌）

de Haas-van Alphen oscillation in the superconducting mixed states of CeRu2 and URu2Si2

Onuki Y, Inada Y, Hedo M, Ohkuni H, Sakurai K, Tokiwa Y, Yamamoto E, Haga Y, Honma T, Takahashi S

PHYSICA B-CONDENSED MATTER   259-61   1060 - 1065   1999年01月 [ 査読有り ]

掲載種別: 研究論文（学術雑誌）

de Haas-van Alphen effect of the heavy-fermion superconductor URu2Si2

Inada Y, Ohkuni H, Hedo M, Tokiwa Y, Sakurai K, Haga Y, Yamamoto E, Honma T, Onuki Y

PHYSICA B-CONDENSED MATTER   259-61   642 - 643   1999年01月 [ 査読有り ]

掲載種別: 研究論文（学術雑誌）

Characterization and flux flow experiments in CeRu2

Hedo M, Kobayashi Y, Inada Y, Yamamoto E, Haga Y, Suzuki J, Metoki N, Onuki Y, Sugawara H, Sato H, Tenya K, Tayama T, Amitsuka H, Sakakibara T

PHYSICA B-CONDENSED MATTER   259-61   688 - 689   1999年01月 [ 査読有り ]

掲載種別: 研究論文（学術雑誌）

Effect of pressure on the flux flow resistance of CeRu2

Kagayama T, Kitakoga R, Oomi G, Honda K, Hedo M, Onuki Y

PHYSICA B-CONDENSED MATTER   259-61   694 - 695   1999年01月 [ 査読有り ]

掲載種別: 研究論文（国際会議プロシーディングス）

Fermi surface of UB₂ studied by the de Haas-van Alphen oscillation

Yamamoto, E; Honma, T; Haga, Y; Inada, Y; Aoki, D; Hedo, M; Yoshida, Y; Yamagami, H; Onuki, Y

PHYSICA B-CONDENSED MATTER   259-61   1085 - 1086   1999年01月 [ 査読有り ]

掲載種別: 研究論文（学術雑誌）

　概要を見る

We observed the de Haas-van Alphen (dHvA) oscillation of UB2 with a hexagonal structure. All of the detected dHvA branches, which are about seven in number, are detected in the limited angle regions. The cyclotron masses are moderately heavy, ranging from 1.2 to 7.7 m0. These features of the Fermi surface are well explained by the 5f-itinerant band theory. © 1999 Elsevier Science B.V. All rights reserved.

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Field-history-dependent peak effect in the superconducting mixed state of CeRu₂

Tenya, K; Yasunami, S; Tayama, T; Amitsuka, H; Sakakibara, T; Hedo, M; Inada, Y; Haga, Y; Yamamoto, E; Onuki, Y

PHYSICA B-CONDENSED MATTER ( ELSEVIER SCIENCE BV )  259-61   692 - 693   1999年01月 [ 査読有り ]

掲載種別: 研究論文（学術雑誌）

　概要を見る

Detailed magnetization measurements of CeRu2 single crystals with different purity are performed in order to clarify whether their peak effects are due to the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) transition. The onset field of the peak shifts to lower held side as the sample becomes impure. Regardless of the purity the Ginzburg-Landau parameter kappa(2) continues to increase on cooling from T-c, indicating little paramagnetic suppression of the superconductivity. These results disagree with the scenario of the FFLO transition. (C) 1999 Elsevier Science B.V, All rights reserved.

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Anisotropic magnetoresistance in UBe<inf>13</inf>

Y. Haga, E. Yamamoto, T. Honma, A. Nakamura, M. Hedo, S. Araki, H. Ohkuni, Y. Onuki

Physica B: Condensed Matter   259-261   627 - 628   1999年 [ 査読有り ]

掲載種別: 研究論文（学術雑誌）

　概要を見る

Angular dependence of the transverse magnetoresistance of a heavy-fermion superconductor UBe13 (Tc = 0.9 K) was measured on a single crystal grown by the Al-flux method. The resistivity decreases with increasing the magnetic field at low temperatures, indicating that a magnetic scattering is suppressed by the magnetic field. We observed a remarkable angular dependence in magnetoresistance at 0.45 K under a constant field of 13 T, showing a minimum at the [1 1 0] direction. This anisotropy of magnetoresistance is observed below 4 K. Since the large resistivity (200 μΩ cm) of this compound at low temperatures is attributed to the magnetic scattering by uranium ions, the present anisotropy in the magnetic scattering at low temperatures would give important information about the ground state of 5f electrons. © 1999 Elsevier Science B.V. All rights reserved.

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Peak effect in CeRu2: Role of crystalline defects

Hedo M, Kobayashi Y, Inada Y, Yamamoto E, Haga Y, Suzuki J, Metoki N, Onuki Y, Sugawara H, Sato H, Tenya K, Tayama T, Amitsuka H, Sakakibara T

JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   67 ( 10 ) 3561 - 3569   1998年10月 [ 査読有り ]

掲載種別: 研究論文（学術雑誌）

Electrodynamics of the superconducting state in CeRu₂

Matsui, H; Yasuda, T; Hedo, M; Settai, R; Onuki, Y; Yamamoto, E; Haga, Y; Toyota, N

JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN ( PHYSICAL SOC JAPAN )  67 ( 10 ) 3580 - 3584   1998年10月 [ 査読有り ]

掲載種別: 研究論文（学術雑誌）

　概要を見る

We have studied the complex conductivity in superconducting and normal metallic slates of CeRu2 by the surface impedance measurements at millimeter-wave frequency of 45.4 GHz. The temperature dependence of the complex conductivity below T-c = 6.2 K exhibits the characteristic behaviors as seen in a conventional superconductor. The coherence peak observed in the real part al provides a strong evidence for a conventional s-wave superconductivity as well as the previous NQR measurements. The temperature dependence of the penetration depth evaluated from the surface reactance at low temperatures has revealed the ratio of 2 Delta(0)/k(B)T(c) = 4.4. The strong-coupling theories suggest the electron-phonon coupling strength with lambda(cp) &lt; 2. These results indicate that CeRu2 is an intermediate strong-coupling superconductor in a clean limit.

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De Haas-van Alphen effect and energy band structure in UB2

Yamamoto E, Haga Y, Honma T, Inada Y, Aoki D, Hedo M, Yoshida Y, Yamagami H, Onuki Y

JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   67 ( 9 ) 3171 - 3175   1998年09月 [ 査読有り ]

掲載種別: 研究論文（学術雑誌）

Anomalous peak effect in CeRu2 and 2H-NbSe2: Fracturing of a flux line lattice

Banerjee SS, Patil NG, Saha S, Ramakrishnan S, Grover AK, Bhattacharya S, Ravikumar G, Mishra PK, Rao TVC, Sahni VC, Higgins MJ, Yamamoto E, Haga Y, Hedo M, Inada Y, Onuki Y

PHYSICAL REVIEW B   58 ( 2 ) 995 - 999   1998年07月 [ 査読有り ]

掲載種別: 研究論文（学術雑誌）

A novel technique to measure magnetisation hysteresis curves in the peak-effect regime of superconductors

Ravikumar G, Rao TVR, Mishra PK, Sahni VC, Banerjee SS, Grover AK, Ramakrishnan S, Bhattacharya S, Higgins MJ, Yamamoto E, Haga Y, Hedo M, Inada Y, Onuki Y

PHYSICA C   298 ( 1-2 ) 122 - 132   1998年03月 [ 査読有り ]

掲載種別: 研究論文（学術雑誌）

Acoustic de Haas van Alphen effect of CeRu2

Suzuki T, Okuda N, Goshima H, Fujita T, Hedo M, Inada Y, Onuki Y, Yamamoto E, Haga Y

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS   177   415 - 416   1998年01月 [ 査読有り ]

掲載種別: 研究論文（学術雑誌）