論文リスト

@article{Ishida1997383,

title = {Cu NQR study of magnetic correlation and superconductivity in a series of Ce1+xCu2+ySi2},

author = {K Ishida and Y Kitaoka and K Kashima and K Asayama and C Geibel and F Steglich},

doi = {10.1016/S0921-4526(96)00729-6},

year  = {1997},

date = {1997-01-01},

journal = {Physica B: Condensed Matter},

volume = {230-232},

pages = {383-386},

abstract = {The anomalous magnetic and superconducting properties in a series of non-stoichiometric Ce1 + xCu2 + ySi2 samples have been investigated by the Cu NQR. In a CeCu2.05Si2 sample regarded as the best quality to date, the superconducting state is within the H-T phase diagram embedded in the unusual A-phase dominated by critical magnetic fluctuations, whereas this A-phase is markedly suppressed in the off-stoichiometric compounds, Ce1.025Cu2Si2 and CeCu2.2Si2 with lower Tc. No difference in the relaxation behavior in the the superconducting state was observed between both type of samples.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Mito19971365,

title = {NMR study in single-layered high-Tc compounds near the antiferromagnetic insulator phase boundary},

author = {T Mito and K Ishida and Y Kitaoka and K Asayama and H Eisaki and S Uchida},

doi = {10.1016/S0921-4534(97)00767-3},

year  = {1997},

date = {1997-01-01},

journal = {Physica C: Superconductivity and its Applications},

volume = {282-287},

number = {PART 3},

pages = {1365-1366},

abstract = {In order to unravel the nature of spin correlations in the vicinity of the transition between antiferromagnetic (AF) and superconducting phases, 63Cu NMR measurements have been carried out for the 8%-Sr doped La2-xSrxCuO4 (LSCO) and hole-reduced Bi2Sr2CuO4 (Bi2201) with Tc = 0 K. It was found that Bi2201 exhibits neither superconductivity nor long-range order from the NMR experiments. 63(1/T1T) in B12201 shows successive decrease down to 100 K, suggesting the presence of the pseudo spin-gap in contrast to its significant increase in 8%-LSCO.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Ishida1997304,

title = {59Co NQR study in superconducting CeCo2},

author = {K Ishida and H Mukuda and Y Kitaoka and K Asayama and H Sugawara and Y Aoki and H Sato},

doi = {10.1016/S0921-4526(97)00183-X},

year  = {1997},

date = {1997-01-01},

journal = {Physica B: Condensed Matter},

volume = {237-238},

pages = {304-306},

abstract = {We have performed 59Co NQR study in superconducting CeCo2 with Tc ∼ 1.4 K in order to investigate the superconducting property. Nuclear spin-lattice relaxation rate of Co, 1/T1 was measured down to 150 mK. 1/T1 is proportional to temperature (T) in the normal state, and decreases exponentially in the superconducting state with the Hebel-Slichter peak just below Tc. T-dependence of 1/T1 in the superconducting state is a typical feature of s-wave superconductivity with 2Δ/kBTc ∼ 2.26, which is remarkably smaller than 3.5 in the BCS superconductor.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Magishi19971115,

title = {63Cu NMR study on spin ladder compounds Sr14-xCaxCu24O41 (x = 9, 11.5)},

author = {K Magishi and S Matsumoto and K Ishida and Y Kitaoka and K Asayama and M Uehara and T Nagata and J Akimitsu},

doi = {10.1016/S0921-4534(97)00671-0},

year  = {1997},

date = {1997-01-01},

journal = {Physica C: Superconductivity and its Applications},

volume = {282-287},

number = {PART 2},

pages = {1115-1116},

abstract = {63Cu NMR measurements for the ladder sites on single crystals Sr14-xCaxCu24O41 (x = 9, 11.5), which consist of simple chains and 2-leg ladders of Cu2+ ions, have been carried out at f = 125.1 MHz for H ∥ b-axis. From respective measurements of the Knight shift and the nuclear spin-lattice relaxation rate, 1/T1, the spin gap in the ladder has been found to be as large as Δ = 250 K (260 K) and 340 K (360 K) for x = 11.5 (x = 9), respectively.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Ishida19971367,

title = {Cu NQR study in Zn- and Ni-doped La1.825Sr0.175CuO4},

author = {K Ishida and T Tanaka and H Yamanaka and T Mito and Y Tokunaga and K Yoshida and K Yamazoe and S Ohsugi and Y Kitaoka and K Asayama},

doi = {10.1016/S0921-4534(97)00769-7},

year  = {1997},

date = {1997-01-01},

journal = {Physica C: Superconductivity and its Applications},

volume = {282-287},

number = {PART 3},

pages = {1367-1368},

abstract = {We have investigated an influence of Zn- and Ni-doping at CuO2 plane in various high-Tc compounds. In optimum-doped LSCO, La1.825Sr0.175CuO4, magnetic Ni as well as nonmagnetic Zn induce a large residual density of states (RDOS) in the superconducting state. The induction of RDOS by slight Zn-doping is considered to be a common feature in optimum-doped high-Tc compounds.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Ihara19971973,

title = {How to make superconducting-anisotropy least in high-Tc cuprate superconductors},

author = {H Ihara and A Iyo and K Tanaka and K Tokiwa and K Ishida and N Terada and M Tokumoto and Y Sekita and T Tsukamoto and T Watanabe and M Umeda},

doi = {10.1016/S0921-4534(97)01057-5},

year  = {1997},

date = {1997-01-01},

journal = {Physica C: Superconductivity and its Applications},

volume = {282},

number = {PART 4},

pages = {1973-1974},

abstract = {The guiding principles to reduce superconducting-anisotropy were derived for high-Tc cuprate superconductors. Based on the principles, we have attained the least superconducting-anisotropy γ=1.6 for a Cu-based CuBa2Ca3Cu4O12-y (Cu-1234) superconductor. Further lower superconducting-anisotropy has been proposed for Cu-1245 (γ=1.3) and Cu-1256 (γ=1.0) Cu-based superconductors.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Maeno1997206,

title = {Electronic states of the superconductor Sr2RuO4},

author = {Y Maeno},

doi = {10.1016/S0921-4534(97)00199-8},

year  = {1997},

date = {1997-01-01},

journal = {Physica C: Superconductivity and its Applications},

volume = {282-287},

number = {PART 1},

pages = {206-209},

abstract = {We discuss the characteristics of the electronic states of the copper-free layered perovskite superconductor Sr2RuO4, which exhibits a sharp transition with Tc up to 1.35 K. The normal state behavior is characterized as an essentially two-dimensional Fermi liquid, consistent with the Fermi surface determined by the de Haas-van Alphen oscillations. The specific heat jump across Tc is consistent with the gap with line nodes, and the unexpectedly large residual T-linear term is suggestive of exotic pairing.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Nakatsuji19971868,

title = {Ca2RuO4: New Mott Insulators of Layered Ruthenate},

author = {S Nakatsuji and S -I Ikeda and Y Maeno},

doi = {10.1143/JPSJ.66.1868},

year  = {1997},

date = {1997-01-01},

journal = {Journal of the Physical Society of Japan},

volume = {66},

number = {7},

pages = {1868-1871},

abstract = {Noncuprate layered perovskite Sr2RuO4 is a highly correlated metal and exhibits superconductivity below Tc ≈ 1.35 K. We have newly synthesized related layered ruthenates Ca2RuO4 in two distinct structural phases with substantially different aspect ratios c/a. Electrical and magnetic measurements show that the two phases are insulating antiferromagnets. We argue that both phases of Ca2RuO4 are Mott insulators. The decrease of the 4d band width in comparison with that of Sr2RuO4, caused by distortions in the RuO2 planes, leads to a Mott-Hubbard-type gap.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Nakatsuji1997729,

title = {New layered perovskite ruthenates: Ca2RuO4},

author = {S Nakatsuji and S -I Ikeda and Y Maeno},

doi = {10.1016/S0921-4534(97)00545-5},

year  = {1997},

date = {1997-01-01},

journal = {Physica C: Superconductivity and its Applications},

volume = {282-287},

number = {PART 2},

pages = {729-730},

abstract = {We have newly synthesized two distinct layered ruthenates of Ca2RuO4. They are both related to Sr2RuO4, the layered perovskite superconductor (Tc ≈ 1K) without copper. In contrast with the highly correlated metal Sr2RuO4, both phases of Ca2RuO4 are Mott insulators.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Bao19971255,

title = {The negative thermopower and the suppression of superconductivity in Nd-doped La2-xBaxCuO4 with x around 1/8},

author = {X Bao and T Fujita and Y Maeno and J Nyhus},

doi = {10.1016/S0921-4534(97)00669-2},

year  = {1997},

date = {1997-01-01},

journal = {Physica C: Superconductivity and its Applications},

volume = {282-287},

number = {PART 3},

pages = {1255-1256},

abstract = {In the study of La2-x-yNdyBaxCuO4 we found that the structural phase transition (OMT-TLT) is observed in a wider range of x (0.10≤x<0.200) than the suppression of superconductivity is evident (0.120≤x≤0.140). A minimum in resistivity and an unusual decrease of the thermopower occur at the same temperature for x around 1/8. Below 30K the thermopower becomes negative associated with the suppression of superconductivity. This means that the suppression of superconductivity is directly caused by a sort of instability in the electronic states.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Shirakawa19977890,

title = {Pressure dependence of superconducting critical temperature},

author = {N Shirakawa and K Murata and S Nishizaki and Y Maeno},

doi = {10.1103/PhysRevB.56.7890},

year  = {1997},

date = {1997-01-01},

journal = {Physical Review B - Condensed Matter and Materials Physics},

volume = {56},

number = {13},

pages = {7890-7893},

abstract = {We studied electrical resistivity of single crystals of an oxide superconductor (Formula presented) under hydrostatic pressure up to 12 kbar. The midpoint (Formula presented) decreases at the rate of 3%/kbar. Anomalous increase of resistivity along the (Formula presented) axis is observed at room temperature with increasing pressure, whereas that in the (Formula presented) plane decreased with pressure as normally expected. © 1997 The American Physical Society.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Mackenzie19972271,

title = {Comment on “extended van hove singularity in a noncuprate layered superconductor Sr2RuO4”},

author = {A P Mackenzie and S R Julian and G G Lonzarich and Y Maeno and T Fujita},

doi = {10.1103/PhysRevLett.78.2271},

year  = {1997},

date = {1997-01-01},

journal = {Physical Review Letters},

volume = {78},

number = {11},

pages = {2271},

abstract = {A Comment on the Letter by T. Yokoya et al., Phys. Rev. Lett. 76, 3009 (1996). The authors of the Letter offer a Reply. © 1997 The American Physical Society.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Nishizaki19971413,

title = {Pairing symmetry of superconducting Sr2RuO4 from specific heat measurements},

author = {S Nishizaki and Y Maeno and S Farner and S Ikeda and T Fujita},

doi = {10.1016/S0921-4534(97)00804-6},

year  = {1997},

date = {1997-01-01},

journal = {Physica C: Superconductivity and its Applications},

volume = {282-287},

number = {PART 3},

pages = {1413-1414},

abstract = {We report the low temperature specific heat of single crystals of non-cuprate layered perovskite superconductor Sr2RuO4(Tc ∼ 1K). In this paper we focus on the relation between the residual value γ0 of the electronic specific heat and the specific-heat jump across Tc. The results provide strong evidence for unconventional superconducting state.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Braden1997248,

title = {Structural analysis of Sr2RuO4},

author = {M Braden and A H Moudden and S Nishizaki and Y Maeno and T Fujita},

doi = {10.1016/S0921-4534(96)00637-5},

year  = {1997},

date = {1997-01-01},

journal = {Physica C: Superconductivity and its Applications},

volume = {273},

number = {3-4},

pages = {248-254},

abstract = {The structure of Sr2RuO4 has been studied by means of neutron single-crystal diffraction as function of temperature. The analysis of the anisotropic atomic displacement parameters (ADP) and the non-existence of superstructure reflections allow one to exclude structural deformations similar to those occurring in Sr2IrO4 and La2CuO4, for short and long range order type. Furthermore, we find no indication for an anomaly in the temperature dependence of the RuO6 octahedron elongation near 140 K where extrema in the resistivity have been reported.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Hussey19971229,

title = {The out-of-plane magnetoresistance of Sr2RuO4},

author = {N E Hussey and A P Mackenzie and J R Cooper and Y Maeno and S Nishizaki and T Fujita},

doi = {10.1016/S0921-4534(97)00806-X},

year  = {1997},

date = {1997-01-01},

journal = {Physica C: Superconductivity and its Applications},

volume = {282-287},

number = {PART 3},

pages = {1229-1230},

abstract = {We report measurements of the out-of-plane magnetoresistance (MR) of Sr2RuO4 (I//c) between 3K and 350K. At low-T, Δρc/ρc is large and positive due to the orbital MR of the carriers. At high T, Δρc/ρc is dominated by a negative and isotropic MR term associated with the non-metallic ρc(T)-We argue that these two contributions to Δρc/ρc(B,T) originate from separate conduction channels along the c-axis and discuss the relevance of these observations to the out-of-plane transport behaviour in the high-Tc cuprates.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Ishida1997R505,

title = {Anisotropic pairing in superconducting Ru NMR and NQR studies},

author = {K Ishida and Y Kitaoka and K Asayama and S Ikeda and S Nishizaki and Y Maeno},

doi = {10.1103/PhysRevB.56.R505},

year  = {1997},

date = {1997-01-01},

journal = {Physical Review B - Condensed Matter and Materials Physics},

volume = {56},

number = {2},

pages = {R505-R508},

abstract = {Ru NMR and nuclear quadrupole resonance studies are reported on single-crystal (Formula presented)0.7 K) with the same layered perovskite structure as (Formula presented). The Pauli spin susceptibility deduced from the Ru Knight shift is found to be largely enhanced by a factor of (Formula presented)5.4 as compared with the value from the band calculation. In the superconducting state, the nuclear spin-lattice relaxation rate (Formula presented) exhibits a sharp decrease with no coherence peak just below (Formula presented) and the (Formula presented)=constant behavior well below (Formula presented) suggesting that the anisotropic pairing state is realized as in heavy-fermion and high-(Formula presented) superconductors. © 1997 The American Physical Society.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Kitaoka1997210,

title = {Spin fluctuation and unconventional pairing in Sr2RuO4},

author = {Y Kitaoka and K Ishida and K Asayama and S Ikeda and S Nishizaki and Y Maeno and K Yoshida and T Fujita},

doi = {10.1016/S0921-4534(97)00202-5},

year  = {1997},

date = {1997-01-01},

journal = {Physica C: Superconductivity and its Applications},

volume = {282-287},

number = {PART 1},

pages = {210-213},

abstract = {Sr2RuCO4 with Tc =0.7 K with the same layered perovskite structure as La2CuO1 is the exchange-enhanced Pauli paramagnet with the two dimensional (2D) electronic structure. The superconductivity of has been found to be unconventional from the nuclear relaxation behavior exhibiting a sharp decrease with no coherence peak just below Tc and the T1T=constant behavior well below Tc. In comparison with the high-Tc Bi2Sr2CaCu2O8+y (Bi2212) and the 3D analogue of exchange-enhanced Pauli paramagnet CeCo2, the similarity and dissimilarity are presented on the normal and superconducting states.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Ishida19971369,

title = {Anisotropic pairing in superconducting Sr2RuO4 (Tc ∼0.7K)},

author = {K Ishida and Y Kitaoka and K Asayama and S Ikeda and S Nishizaki and Y Maeno and K Yoshida and T Fujita},

doi = {10.1016/S0921-4534(97)00770-3},

year  = {1997},

date = {1997-01-01},

journal = {Physica C: Superconductivity and its Applications},

volume = {282-287},

number = {PART 3},

pages = {1369-1370},

abstract = {Ru NQR study in single crystals of Sr2RuO4 (Tc ∼ 0.7K) has been carried out to investigate a superconducting pairing state. In the superconducting state, 1/T1 exhibits a sharp decrease with no coherence peak just below Tc and the T1T=constant behavior well below Tc, suggesting that the anisotropic pairing state is realized as in high-Tc and heavy-fermion superconductors.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Maeno19971405,

title = {Two-Dimensional Fermi Liquid Behavior of the Superconductor Sr2RuO4},

author = {Y Maeno and K Yoshida and H Hashimoto and S Nishizaki and S -I Ikeda and M Nohara and T Fujita and A P Mackenzie and N E Hussey and J G Bednorz and F Lichtenberg},

doi = {10.1143/JPSJ.66.1405},

year  = {1997},

date = {1997-01-01},

journal = {Journal of the Physical Society of Japan},

volume = {66},

number = {5},

pages = {1405-1408},

abstract = {We report detailed normal state measurements of the resistivity, magnetic susceptibility and specific heat of high-quality single crystals of Sr2RuO4, the only copper-free, layered perovskite superconductor (Tc ≈ 1 K). It is intriguing that despite its very strong anisotropy (the ratio of the interlayer to in-plane resistivity exceeds 500) arising from the essentialy two-dimensional Fermi surface, the normal state properties are consistent with a universal description for a strongly correlated Fermi liquid. Therefore, Sr2RuO4 serves as an ideal reference material for the investigation of the limits of applicability of Fermi liquid theory to other highly correlated layered compounds, including high-Tc cuprates.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Ikeda19961599,

title = {Two distinct structural phases in Sr3-xCaxRu2Oy},

author = {S Ikeda and Y Maeno and H Muranishi and T Fujita},

doi = {10.1007/BF00753928},

year  = {1996},

date = {1996-01-01},

journal = {Journal of Low Temperature Physics},

volume = {105},

number = {5-6},

pages = {1599-1604},

abstract = {Non-cuprate layered perovskite Sr2RuO4, which is an analogue of (La,Sr)2 CuO4, exhibits superconductivity below Tc ≈ 1K. We have synthesized a new system Sr3-xCaxRu2Oy and found the solubility of Ca to be at least as much as x = 2. These samples are not superconductive down to 2K but magnetically ordered. The x dependence of the lattice parameters and that of Tmag clearly indicate that there are at least two distinct structural phases in Sr3-xCaxRu2Oy. © 1996 Plenum Publishing Corporation.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Yoshida1996519,

title = {Anisotropic superconductivity of Sr2RuO4},

author = {K Yoshida and Y Maeno and S Nishizaki and T Fujita},

doi = {10.1016/0921-4534(95)00728-8},

year  = {1996},

date = {1996-01-01},

journal = {Physica C: Superconductivity and its Applications},

volume = {263},

number = {1-4},

pages = {519-522},

abstract = {We report the upper critical field Hc2 of single crystalline Sr2RuO4, which is the only known layered-perovskite superconductor without copper. The ratio Hc2∥ab/Hc2∥c = 26 indicates that the ruthenate is a highly anisotropic superconductor. In addition, we found a peculiar second dissipation peak only when the flux lines, as well as their induced motions, are within the ab-planes.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Ikeda1996558,

title = {Sr2CaRu2Oy: A new phase of layered perovskite},

author = {S Ikeda and Y Maeno and M Nohara and T Fujita},

doi = {10.1016/0921-4534(95)00718-0},

year  = {1996},

date = {1996-01-01},

journal = {Physica C: Superconductivity and its Applications},

volume = {263},

number = {1-4},

pages = {558-561},

abstract = {We have synthesized a new phase of layered perovskite Sr2CaRu2Oy related to Sr3Ru2O7. The Ca-substitution weakens the antiferromagnetic correlations and reduces the magnetic transition temperature from 15 to 3 K. The antiferromagnetic correlation between Ru4+ spins in Sr2CaRu2Oy can be varied by adjusting the oxygen content y.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Maeno19961577,

title = {Normal-state and superconducting properties of Sr2RuO4},

author = {Y Maeno and S Nishizaki and K Yoshida and S Ikeda and T Fujita},

doi = {10.1007/BF00753925},

year  = {1996},

date = {1996-01-01},

journal = {Journal of Low Temperature Physics},

volume = {105},

number = {5-6},

pages = {1577-1586},

abstract = {We discuss some of the current issues on the copper-free layered perovskite superconductor Sr2RuO4, for which a sharp transition at Tc = 1.2 K has been reproducibly obtained. The normal state is characterized as an essentially two-dimensional Fermi liquid, and the coherent interlayer transport is established only at low temperatures. The cylindrical Fermi surface observed by de Haas-van Alphen experiments is consistent with other thermodynamic and transport properties. Although the specific heat jump across Tc confirms the bulk superconductivity, the large residual T-linear term which correlates with the variation in Tc is unusual and suggestive of unconventional pairing. © 1996 Plenum Publishing Corporation.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Yoshida19961593,

title = {Crossover from 3D to 2D metallic conduction in Sr2RuO4},

author = {K Yoshida and Y Maeno and S Nishizaki and S Ikeda and T Fujita},

doi = {10.1007/BF00753927},

year  = {1996},

date = {1996-01-01},

journal = {Journal of Low Temperature Physics},

volume = {105},

number = {5-6},

pages = {1593-1598},

abstract = {We have investigated the normal-state conduction of superconducting Sr2RuO4 (Tc ∼ 1K), which is isostructural to La2-xSrxCuO4. The resistivity of single crystals shows a crossover at TM ∼ 130K from 3D metallic conduction at lower temperatures to 2D one at higher temperatures. Concerning the temperature dependence of the out-of-plane resistivity, we present a systematic interpretation based on competition between the life time of the quasiparticles and the time for the quasiparticles to travel between the adjacent RuO2 planes. © 1996 Plenum Publishing Corporation.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Nakamura1996282,

title = {Transport properties of detwinned crystals of La2-xSrxCuO4},

author = {F Nakamura and M Kodama and S Sakita and Y Maeno and T Fujita},

doi = {10.1016/0921-4534(95)00730-X},

year  = {1996},

date = {1996-01-01},

journal = {Physica C: Superconductivity and its Applications},

volume = {263},

number = {1-4},

pages = {282-285},

abstract = {We report out-of-plane and in-plane resistivities of detwinned La2-xSrxCuO4 crystals. It is found that the conduction along the c-direction within the twin boundaries is not at all negligible compared with the intrinsic conduction along the c-axis within a domain. The anisotropy in the in-plane resistivity is interpreted as due to anisotropic scattering by phonons.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Yoshino19961548,

title = {Thermopower of a Layered Perovskite Superconductor, Sr2RuO4},

author = {H Yoshino and K Murata and N Shirakawa and Y Nishihara and Y Maeno and T Fujita},

doi = {10.1143/JPSJ.65.1548},

year  = {1996},

date = {1996-01-01},

journal = {Journal of the Physical Society of Japan},

volume = {65},

number = {6},

pages = {1548-1550},

abstract = {Thermopower of a layered perovskite superconductor, Sr2RuO4, is studied. The magnitude of the thermopower in the conducting plane is about 29 μ.V · K-1 at 300K. Above 4.2 K thermopower increases almost linearly with temperature, and it tends to saturate at high temperature. Thermopower is positive in the measured temperature range. The temperature derivative of thermopower shows a sharp change at about 20 K where no anomaly has been reported for other physical properties of Sr2RuO4.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Kato1996482,

title = {Transport and magnetic properties of the spin-1/2 ladder system (Sr,A)14Cu24O41 (A = Ba and Ca)},

author = {M Kato and K Shiota and S Ikeda and Y Maeno and T Fujita and Y Koike},

doi = {10.1016/0921-4534(95)00790-3},

year  = {1996},

date = {1996-01-01},

journal = {Physica C: Superconductivity and its Applications},

volume = {263},

number = {1-4},

pages = {482-485},

abstract = {We have investigated the transport and magnetic properties of the spin-1/2 ladder system with two legs, Sr14-xAxCu24O41 (A = Ba and Ca). For x - 0, the electrical resistivity ρ exhibits semiconductive behavior. It becomes more insulating with the increase in x(Ba), while it becomes more conductive with the increase in x(Ca). The broad peak of the magnetic susceptibility around 80 K has been studied in detail. Subtracting the Curie component at low temperatures, the remainder of the susceptibility Xs(T) decreases towards zero with decreasing temperature below ∼ 80 K, which implies the presence of a spin gap. The value of Xs(T) decreases with the increase in x(Ba), while it tends to increase with the increase in x(Ca). Moreover, for the samples with x = 0 annealed under various atmospheres, p tends to decrease and Xs(T) increases with the decrease in oxygen content. These properties are discussed in terms of the redistribution of holes between the two different sites of Cu. It seems that the observed spin-gap behavior is due to Cu2+ spins in the CuO2-chain rather than in the Cu2O3-plane.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Lanzara199693,

title = {Temperature dependent local structure of the CuO2 plane in the 1/8 doped La1.875Ba0.125CuO4 system},

author = {A Lanzara and N L Saini and T Rossetti and A Bianconi and H Oyanagi and H Yamaguchi and Y Maeno},

doi = {10.1016/0038-1098(95)00590-0},

year  = {1996},

date = {1996-01-01},

journal = {Solid State Communications},

volume = {97},

number = {2},

pages = {93-96},

abstract = {Local structure of the Cu site in the 1/8 doped insulating La1.875Ba0.125CuO4 system has been studied by Cu K-edge extended x-ray absorption spectra (EXAFS). The correlated Debye-Waller factor of the Cu-O(planar) pairs shows an anomalous increase below ∼70K indicating structural fluctuations in the CuO2 lattice. The results are in agreement with the recent diffraction studies showing 70K as an onset temperature for a superstructure peak due to charge modulation in the system, below the transition from average low temperature orthorhombic (LTO) to average low temperature tetragonal (LTT) structure.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Nakamura199610061,

title = {Pressure dependence of out-of-plane conduction},

author = {F Nakamura and M Kodama and S Sakita and Y Maeno and T Fujita and H Takahashi and N Môri},

doi = {10.1103/PhysRevB.54.10061},

year  = {1996},

date = {1996-01-01},

journal = {Physical Review B - Condensed Matter and Materials Physics},

volume = {54},

number = {14},

pages = {10061-10064},

abstract = {Pressure dependence of out-of-plane resistivity (Formula presented) has been investigated in an optimally-doped high-(Formula presented) cuprate (Formula presented)(Formula presented)(Formula presented). By applying pressure, we found a drastic decrease in (Formula presented) which reaches 50% at P=8 GPa. This surprisingly large P dependence implies that the thermal contraction along the c axis is significantly reflected in the (Formula presented)(T) curve, leading to a metal-like term; hence (Formula presented)(Formula presented)(Formula presented) is essentially characterized as a two-dimensional metal modified with nonmetallic conduction between (Formula presented) layers. Tunneling is suggested for a possible mechanism for (Formula presented). © 1996 The American Physical Society.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Nakamura1996915,

title = {Pressure effects of resistivity along the c axis in La2-xSrxCuO4},

author = {F Nakamura and M Kodama and N Kikugawa and S Sakita and Y Maeno and T Fujita and H Takahashi and N Môri},

doi = {10.1007/BF00768499},

year  = {1996},

date = {1996-01-01},

journal = {Journal of Low Temperature Physics},

volume = {105},

number = {3-4},

pages = {915-920},

abstract = {Out-of-plane resistivity ρc(T) of optimally-doped high-Tc superconductor La2-xSrxCuO4 has been investigated under hydrostatic pressure up to 8GPa. We found a drastic decrease in ρc which reaches 50% at 8GPa. The large change of ρc is understood as due to a small variation of the lattice parameter c. In comparison with a change of ρc(T) estimated from a change of c due to thermal contraction, we conclude that the well known temperature-linear dependence of ρc is apparent metallic one; essentially ρc is nonmetallic over the whole temperature range, and can be described in terms of tunneling or quantum hopping conduction between CuO2 layers. Such tunneling conduction is enhanced by the scattering in the CuO2 plane at the oxygen defects which affect the in-plane resistivity only very weakly. © 1996 Plenum Publishing Corporation.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Yamanaka1996516,

title = {Electronic Raman scattering spectra of Sr2RuO4 single crystals},

author = {A Yamanaka and N Asayama and M Sasada and K Inoue and M Udagawa and S Nishizaki and Y Maeno and T Fujita},

doi = {10.1016/0921-4534(95)00727-X},

year  = {1996},

date = {1996-01-01},

journal = {Physica C: Superconductivity and its Applications},

volume = {263},

number = {1-4},

pages = {516-518},

abstract = {Electronic Raman scattering has been measured in Sr2RuO4 single crystals. We observe that the electronic Raman scattering exhibits a structureless continuum spectrum extending to beyond 4000 cm-1. The scattering rate Γ of charge carriers, estimated from the observed Raman spectrum, shows an ω-linear increase in the higher-energy region above 500 cm-1. This indicates strong correlation between charge carriers. In the lower-energy region the scattering rate is almost constant, Γ(0) ∼ 300 cm-1. This value is essentially the same as that observed in high-Tc copper oxides.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Mackenzie1996510,

title = {Calculation of thermodynamic and transport properties of Sr2RuO4 at low temperatures using known Fermi surface parameters},

author = {A P Mackenzie and S R Julian and A J Diver and G G Lonzarich and N E Hussey and Y Maeno and S Nishizaki and T Fujita},

doi = {10.1016/0921-4534(95)00770-9},

year  = {1996},

date = {1996-01-01},

journal = {Physica C: Superconductivity and its Applications},

volume = {263},

number = {1-4},

pages = {510-515},

abstract = {We report the results of a study of quantum oscillations in the layered perovskite superconductor Sr2RuO4. All three predicted sheets of the Fermi surface have been observed, and we show how the measured Fermi surface parameters and quasiparticle cyclotron masses can be used to make successful quantitative predictions of a number of physical properties that can be measured independently.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Inoue1996175,

title = {Spectroscopic manifestation of mass renormalization in a layered 4d-electron superconductor Sr2RuO4},

author = {I H Inoue and Y Aiura and Y Nishihara and Y Haruyama and S Nishizaki and Y Maeno and T Fujita and J G Bednorz and F Lichtenberg},

year  = {1996},

date = {1996-01-01},

journal = {Journal of Electron Spectroscopy and Related Phenomena},

volume = {78},

pages = {175-178},

abstract = {Recently discovered layered-perovskite superconductor Sr2RuO4 shows significant spectral weight redistribution in its low energy photoemission spectrum. This suggests the existence of strong electron correlation in the system. Renormalized mass is estimated by the phenomenological analysis of the spectrum. The importance of a momentum-dependent part of the self-energy is discussed.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Tokunaga19961139,

title = {Coexistence of magnetic ordering induced by Ni spins and superconductivity in Ni-substituted YBa2Cu3O7-Cu NQR study-},

author = {Y Tokunaga and K Ishida and Y Kitaoka and K Asayama},

doi = {10.1007/BF02583877},

year  = {1996},

date = {1996-01-01},

journal = {Czechoslovak Journal of Physics},

volume = {46},

number = {SUPPL. 2},

pages = {1139-1140},

abstract = {From the Cu NQR measurements ill tlae superconducting state of Ni-substituted YBa2(Cu1-xNix)3O7, it has been found that the nuclear spin-lattice relaxation rate, 1/T1 and the spin echo decay rate, l/T2 of 63Cu are largely enhanced around TM = 2.5 and 3.5 K for 7 and 10% Ni doping, respectively. Below TM, the Cu NQR spectrum has revealed the presence of distributed internal fields at Cu nuclei in the CuO2 plane with a maximum value of ~2.5 kOe. From these results, the magnetic ordering is concluded to take place by the indirect exchange coupling among Ni moments with S = 1/2 mediated by the antiferromagnetic Cu spin polarization around Q = (π/a, π/a) in the CuO2 plane. We propose that the superconductivity coexist with the magnetic ordering due to the d wave nature with node line around Q = (π/a, π/a).},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Mito19961145,

title = {Spin correlation in superconducting La1.92Sr0.08CuO4 near the antiferromagnetic insulator phase boundary},

author = {T Mito and Y Kitaoka and T Tanaka and K Ishida and K Asayama},

year  = {1996},

date = {1996-01-01},

journal = {Czechoslovak Journal of Physics},

volume = {46},

number = {SUPPL. 2},

pages = {1145-1146},

abstract = {In order to unravel tile nature of spin correlation in the vicinity of the antiferromagnetic (AF) phase boundary, the 63Cu nuclear spin lattice relaxation rate, 63(1/T1), has been measured for the 8%-Sr doped superconducting (SC) La2-xSrxCuO4 (LSCO) by Cu NMR and NQR techniques. The temperature dependence of 63(1/T1T) has revealed a continuous increase down to Tc without the spin pseudogap behavior observed in underdoped YBa2Cu3O6+x and YBa2Cu4O8.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Asayama19963187,

title = {NMR of high Tc superconductors},

author = {K Asayama and Y Kitanka and G -Q Zheng and K Ishida and K Magishi and T Mito and Y Tokunaga},

doi = {10.1007/BF02548129},

year  = {1996},

date = {1996-01-01},

journal = {Czechoslovak Journal of Physics},

volume = {46},

number = {SUPPL. 6},

pages = {3187-3194},

abstract = {Results of our NMR measurements of high Tc superconductors are reviewed. From systematic measurements of NQR frequency, Knight shift, nuclear spin lattice relaxation rate and nuclear transverse relaxation rate over a wide hole concentration range from light to heavy doped compounds together with the impurity and pressure effect, following results are concluded. The numbers of the holes at the respective sites of Cu and O site in the CuO2 plane govern the several physical properties of the system. There are optimum values of these hole numbers to produce highest Tc. The superconducting properties are well explained consistently by the d-wave pairing model. Tc is found to be correlated intimately with the antiferromagnetic spin fluctuation parameters that governs the nuclear relaxation. The mechanism for the superconductivity is magnetic in origin.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Asayama1996478,

title = {NMR study of high-TC superconductors},

author = {K Asayama and Y Kitaoka and G -Q Zheng and K Ishida and K Magishi},

doi = {10.1016/0921-4526(96)00153-6},

year  = {1996},

date = {1996-01-01},

journal = {Physica B: Condensed Matter},

volume = {223-224},

number = {1-4},

pages = {478-483},

abstract = {Recent NMR study of high-TC superconductors carried out by Osaka group is reviewed. NQR frequency vQ, Knight shift K, T1 of 63Cu and 17O were measured over a wide hole doping range from light-to heavy-doped systems, LSCO, YBCO, HBCCO, BSCCO, TBCCO and TBCO, together with impurity and pressure effect. By analysing vQ, K and T1, the local hole numbers of Cu and O at the CuO2 plane, n(Cu) and n(O) the relative magnitude of the uniform susceptibility, χ0 and the low-frequency component of the antiferromagnetic spin fluctuations (AFSF), χQ/Γ (χQ is the staggered susceptibility and Γ is the characteristic energy of the spin fluctuation at q = 0) are obtained. The relation between n(Cu), n(O) and χQ, χQ/Γ, TC, etc. were discussed. There are optimum values of n(Cu)/2n(O) and n(Cu) + 2n(O) to give maximum TC. The NMR results in the superconducting state are well-explained by d-wave pairing model. The result is consistent with the AFSF mediated superconducting model.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Asayama1996221,

title = {NMR studies of high Tc superconductors},

author = {K Asayama and Y Kitaoka and G -Q Zheng and K Ishida},

doi = {10.1016/0079-6565(95)01025-4},

year  = {1996},

date = {1996-01-01},

journal = {Progress in Nuclear Magnetic Resonance Spectroscopy},

volume = {28},

number = {3-4},

pages = {221-253},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Ishida1996793,

title = {Ru NMR and NQR Studies in CeRu2},

author = {K Ishida and H Mukuda and Y Kitaoka and K Asayama and Y Onuki},

doi = {10.1515/zna-1996-5-673},

year  = {1996},

date = {1996-01-01},

journal = {Zeitschrift fur Naturforschung - Section A Journal of Physical Sciences},

volume = {51},

number = {5-6},

pages = {793-796},

abstract = {We have carried out Ru NMR and NQR measurements in superconductor CeRu2 having Tc = 6.1 K in the temperature range of 1.3- 30 K. From the 99Ru NMR in 10.2 T above Hc2},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Ishida1996371,

title = {Spin correlations in the normal state of a Bi2Sr2CaCu2O8 single crystal},

author = {K Ishida and Y Kitaoka and K Asayama and K Kadowaki and T Mochiku},

doi = {10.1016/0921-4534(95)00756-3},

year  = {1996},

date = {1996-01-01},

journal = {Physica C: Superconductivity and its Applications},

volume = {263},

number = {1-4},

pages = {371-374},

abstract = {The Gaussian component of the spin-echo decay rate, 1/T2G of 63Cu mediated by magnetic fluctuations, has been measured in the normal state on single crystal Bi2Sr2CaCu2O8 (Bi2212). The temperature dependence of 1/T2G bears a resemblance to that of 1/T1T, exhibiting a peak at around 140 K. It has been found that the T-dependence of 1/T2G quite contrasts with those in the underdoped compounds such as YBa2Cu3O6.63 and YBa2Cu4O8, although the T-dependences of the Knight shift and 1/T1T seem to be analogous to each other. From the analyses taking all sets of data, such as 1/T2G, the spin susceptibility and 1/T1T, the character of spin fluctuations in Bi2212 is deduced to be similar to that in YBa2Cu3O7, which is considered to be at optimum hole doping, although the T-dependences of 1/T1T, 1/T2G and Ks(T) are seemingly different from each other.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Ishida1996531,

title = {Al NMR Probe of Local Moments Induced by an Al Impurity in High-Tc Cuprate La1.85Sr0.15CuO4},

author = {K Ishida and Y Kitaoka and K Yamazoe and K Asayama and Y Yamada},

doi = {10.1103/PhysRevLett.76.531},

year  = {1996},

date = {1996-01-01},

journal = {Physical Review Letters},

volume = {76},

number = {3},

pages = {531-534},

abstract = {27Al and 63Cu NMR measurements in 3% Al-doped La1.85Sr0.15CuO4 (LSCO) have revealed that the T dependences of the Knight shift, 27K(T), and the nuclear-spin-lattice relaxation rate, 27(1/T1), are dominated by local moments induced at neighboring Cu sites by the Al impurity. These experiments prove that spin fluctuation of induced moments is mainly due to the local spin-exchange coupling, Jsd, with conducting holes. This novel T dependence of 27(1/T1) has led to a reliable estimation of Jsd = 0.055eV, and the extraction of the Tc Δ Tc = 0.62K/Al% based on the magnetic pair-breaking scheme, which is by more than 1 order of magnitude smaller than the experimental value of ΔTc = 23K/Al%. © 1996 American Physical Society.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Ishida19962341,

title = {93Nb NQR Study in Layered Superconducting 2H-NbSe2},

author = {K Ishida and Y Niino and G -Q Zheng and Y Kitaoka and K Asayama and T Uhtani},

doi = {10.1143/JPSJ.65.2341},

year  = {1996},

date = {1996-01-01},

journal = {Journal of the Physical Society of Japan},

volume = {65},

number = {7},

pages = {2341-2342},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Ishida1996329,

title = {Antiferromagnetic Nuclear Resonance of Cu in Infinite-Layer Compounds, SrCuO2 and Ca0.9Sr0.1CuO2 -Comparison between Hyperfine Coupling Constant in a CuO2 Plane and in a Spin-Ladder System-},

author = {K Ishida and Yo. Tokunaga and Y Kitaoka and K Asayama and M Azuma and Z Hiroi and M Takano},

doi = {10.1143/JPSJ.65.329},

year  = {1996},

date = {1996-01-01},

journal = {Journal of the Physical Society of Japan},

volume = {65},

number = {1},

pages = {329-330},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Matsumoto1996R11942,

title = {Competition between the singlet-spin liquid state and the magnetic ground state in a two-chain spin-½ antiferromagnetic ladder compound LaC: A NMR study},

author = {S Matsumoto and Y Kitaoka and K Ishida and K Asayama and Z Hiroi and N Kobayashi and M Takano},

doi = {10.1103/PhysRevB.53.R11942},

year  = {1996},

date = {1996-01-01},

journal = {Physical Review B - Condensed Matter and Materials Physics},

volume = {53},

number = {18},

pages = {R11942-R11945},

abstract = {The magnetic characteristics of LaCu(Formula presented) comprising an antiferromagnetic two-chain spin-½ ladder have been investigated by (Formula presented) NMR measurements. The ground state of this compound was suggested from susceptibility measurements to be the singlet-spin liquid state. The present experiments have, however, revealed that LaCu(Formula presented) is not in such a spin-liquid state, but rather a magnetic ordering takes place below (Formula presented) K as evidenced by the large enhancement of the nuclear spin-lattice relaxation rate, ((Formula presented)) and of the spin-echo decay rate, (Formula presented) leading to the disappearance of the Cu NMR signal. This magnetic ordered state has been found to be suppressed by substituting Sr for La by 5%, i.e., by hole doping. © 1996 The American Physical Society.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Ishida19962827,

title = {Spin correlation and spin gap in quasi-one-dimensional spin-1/2 cuprate oxides: A NMR study},

author = {K Ishida and Y Kitaoka and Y Tokunaga and S Matsumoto and K Asayama and M Azuma and Z Hiroi and M Takano},

doi = {10.1103/PhysRevB.53.2827},

year  = {1996},

date = {1996-01-01},

journal = {Physical Review B - Condensed Matter and Materials Physics},

volume = {53},

number = {5},

pages = {2827-2834},

abstract = {The Cu-NMR nuclear relaxation rate, (Formula presented)(1/(Formula presented)) and Gaussian spin-echo decay rate, (Formula presented)(1/(Formula presented)) have been measured in order to investigate the low-energy spin dynamics in the quasi-one-dimensional (1D) spin-1/2 antiferromagnetic (AF) cuprates such as (Formula presented)(Formula presented) with single chain, (Formula presented) at ambient pressure (AP) with zigzag chain coupled by weak ferromagnetic exchange interaction, (Formula presented)(Formula presented) and (Formula presented)(Formula presented)(Formula presented) comprising of two- and three-leg ladder, respectively with isotropic AF exchange interaction along and between chains. In (Formula presented)(Formula presented), 1/(Formula presented) stays constantly close to the 3D magnetic ordering temperature, (Formula presented)∼10 K, dominated by dissipation of overdamped spinons gas as shown theoretically by Sachdev. By contrast, in AP-(Formula presented), 1/(Formula presented) below around 100 K decreases markedly down to the 3D magnetic ordering temperature, (Formula presented)∼3 K, providing a signature that the frustrated ferromagnetic interaction between CuO zigzag chains makes the spin gap open. In the spin-1/2 ladder compounds of (Formula presented)(Formula presented) and (Formula presented)(Formula presented)(Formula presented) consisting of two- and three-leg, respectively, the former was demonstrated in the literatures to have the spin gap amounting to a half of AF exchange constant, J/2 where J=1300 K. For the latter, on the other hand, the magnetic coherence length, ξ(T) grows up according to ξ(T)∼1/(T-θ) and as a result, the magnetic ordering emerges around 50-60 K accompanying the divergence of 1/(Formula presented). In the compounds composed of single and triple chains, it is shown that there is no analog of renormalized classical region identified in the 2D spin-1/2 cuprate such as (Formula presented)(Formula presented), but the spin dynamics is in the quantum critical regime over wide T range due to the finite size of chains, even though the 3D magnetic ordering takes place at very low temperature. This is considered because the spin correlators have a power-law decay only along the chain, but between chains is limited to the number of chains in contrast to the 2D square lattice. For the compounds with two chains, the exchange coupling between chains leads to the formation of spin gap phase regardless of whether its sign is antiferromagnetic or ferromagnetic. A result on doping into the two-leg ladder, (Formula presented)(Formula presented) is argued in terms of the localization effect of carriers. © 1996 The American Physical Society.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Maeno19963097,

title = {Fermi liquid properties and superconductivity of Sr2RuO4},

author = {Y Maeno and K Yoshida},

doi = {10.1007/BF02548115},

year  = {1996},

date = {1996-01-01},

journal = {Czechoslovak Journal of Physics},

volume = {46},

number = {SUPPL. 6},

pages = {3097-3104},

abstract = {Sr2RuO4 (Tc≈1K) is the first copper-free superconductor isostructural to high-Tc copper oxides. The normal state is characterized as an essentially two-dimensional Fermi liquid, with coherent interlayer transport established only at low temperatures. Superconductivity is highly anisotropic but qualitatively different from high-Tc superconductivity because of the long coherence length normal to the layer. We will review the current status of the extensive studies on this superconductor and make comparison with the high-Tc superconductors.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Ishida19961093,

title = {Ru NMR and NQR Studies in Superconducting Sr2RuO4 with Tc = 0.7K},

author = {K Ishida and Y Kitaoka and K Asayama and S Ikeda and Y Maeno and T Fujita},

year  = {1996},

date = {1996-01-01},

journal = {Czechoslovak Journal of Physics},

volume = {46},

number = {SUPPL. 2},

pages = {1093-1094},

abstract = {Ru NMR and NQR studies have been made in the superconducting single crystal Sr2RuO4 (Tc = 0.7K) in order to investigate an electronic state in the RuO2 plane. It has been found that the T1T and the Knight shift stay constantly between 1.4 and 4.2 K, which allows us to estimate the Stoner factor, α and the enhancement factor of the Korringa product K(α) to be 0.92 and 1, respectively. From these results, it is shown that Sr2RuO4 is characterized by dominant ferromagnetic fluctuations and two-dimensional(2-D) electronic structure.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Udagawa19961115,

title = {Raman scattering of La2CuO4+δ},

author = {M Udagawa and T Minami and N Ogita and F Nakumura and Y Maeno and T Fujita},

doi = {10.1007/BF02583865},

year  = {1996},

date = {1996-01-01},

journal = {Czechoslovak Journal of Physics},

volume = {46},

number = {SUPPL. 2},

pages = {1115-1116},

abstract = {Raman scattering spectra of La2CuO4+δ (δ = 0, 0.014, and 0.063) have been measured. With increasing δ, the intensity of the La vibration increases and its energy decreases at room temperature. This result suggests that the La vibration couples with the charge density wave due to the carrier doping. In the temperature dependence of La2CuO4.063 (Tc = 40K), we have observed new mode at 120cm-1 below 220K. This mode is assigned as the vibration of the excess oxygen along the c-axis. This result shows the anomaly at 250K can be attributed to the freezing of the itinerancy of the excess oxygen.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Inoue19962699,

title = {Spectrai weight redistribution in Ca1-xSrxVO3 and Sr2RuO4},

author = {I H Inoue and H Makino and Y Aiura and I Hase and Y Maeno and Y Haruyama and S Nishizaki and T Fujita and Y Nishihara},

doi = {10.1007/BF02570336},

year  = {1996},

date = {1996-01-01},

journal = {Czechoslovak Journal of Physics},

volume = {46},

number = {SUPPL. 5},

pages = {2699-2700},

abstract = {Quasiparticle spectra of the Ca1-xSrxVO3 and Sr2RuO4 single-crystals are reported. The spectra have been measured around 14K for Ca1-xSrxVO3 and 80K for Sr2RuO4 by high-resolution angle-integrated photoemission spectroscopy. Large spectral weight redistribution has been observed in both systems, suggesting an importance of the electron correlation.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Gough199673,

title = {The low temperature microwave properties of GdBa2Cu3O7-δ and Sr2RuO4},

author = {C E Gough and R J Ormeno and M A Hein and A Sibley and J J Wingfield and J Powell and A Porch and G Yang and Y Maeno and Z Q Mao},

year  = {1996},

date = {1996-01-01},

journal = {Journal of Superconductivity and Novel Magnetism},

volume = {14},

number = {1},

pages = {73-79},

abstract = {Measurements of the microwave surface resistance Rs and reactance Xs of GdBa2Cu3O7-δ and Sr2RuO4 single crystals are reported in the temperature range 0.4 to 25 K at frequencies from 10 to 20 GHz, using a hollow dielectric resonator technique. The GdBa2Cu3O7-δ measurements are interpreted in terms of antiferromagnetic alignment of the Gd spins, resulting in a Nèel transition at 2.25 K, with a strongly temperature spin relaxation time both above and below the transition. Above Tc = 1.45 K, the normal state surface impedance of the suspected p-wave superconductor Sr2RuO4 agrees rather well with that expected from dc measurements; however, below Tc, we observe an unusual increase in the surface reactance, which we attribute to a long electron relaxation time. Using a two-fluid model, we obtain a normal fluid component that decreases almost linearly with temperature and extrapolates to a finite low-temperature value. © 2001 Plenum Publishing Corporation.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}