Grant-in-Aid for International Scientific Research.
|Section||Joint Research .|
|Research Institution||HIROSHIMA UNIVERSITY|
FUJITA Toshizo Hiroshima Univ., Dept.of Physics, Professor, 理学部, 教授 (20004369)
BRADEN Marlc フランス国立サクレ原子核研究所, リオンーブリリアン施設, 研究員
MOUDDEN A.Ha フランス国立サクレ原子核研究所, リオンーブリリアン施設, 主任研究員
NAKAMURA Fumihiko Hiroshima Univ., Dept.of Physics, Associate, 理学部, 助手 (40231477)
MAENO Yoshiteru Kyoto Univ., Graduatc School of Sci., Associate Professor, 大学院理学研究科, 助教授 (80181600)
SUZUKI Takashi Hiroshima Univ., Dept.of Physics, Associate Professor, 理学部, 助教授 (00192617)
MARHUS Brade フランス国立サクレ原子核研究所, リオンーブリリアン施設, 研究員
A.HAMID Moud フランス国立サクレ原子核研究所, リオンーブリリアン施設, 主任研究員
MOUDDEN A.Hamid Laboratoire Leon Brillouin, CEA-CNRS,Chief Researcher
BRADDEN Markus Laboratoire Leon Brillouin, CEA-CNRS,Researcher
|Project Fiscal Year
1996 – 1996
Completed(Fiscal Year 1996)
|Budget Amount *help
¥5,200,000 (Direct Cost : ¥5,200,000)
Fiscal Year 1996 : ¥5,200,000 (Direct Cost : ¥5,200,000)
|Keywords||high-temperature superconductors / single crystal / lattice instability / neutron scottering / de Haas van Alphen effect / Fermi surface / 高温超伝導体 / 単結晶 / 格子不安定性 / 中性子散乱 / ドハース・ファンアルフェン効果 / フェルミ面 / ドハース・ファン・アルフェン効果|
In the vicinity of the doping level and the temperature range where the high-temperature superconductivity appcars, materials often encounter the lattice instability. From our acoustic study, the lattice instability and supercondueting transition are suggested to compete with each other in La_<2-x>Sr_xCuO_4 (LSCO). The aim of this research project is to inverstigatethe relation between the lattice instability and the superconductivity in LSCO and the reference material Sr_2RuO_4 (SRO). In collaboratin with a French group at Saclay, we (Japanese group) performed neutron experiments on our single-crystalline samples of LSCO and SRO.For SRO,we collaborated also with a British group at Cambridge on the deHaas van Alphen (dHvA) experiments to map the Fermi surface of SRO.Our works can be summarized as follows.
1.We grew high-quality single crystals of LSCO,Nd-doped LSCO (LNSOC) and SRO.Part of the crystals were used for the X-ray diffraction, ultrasonic experiments, specific heat measurement
s, dilatometry and measurements of transport coefficients. Another part of the crystals were sent to Saclay for the neutron experiments and some SRO crystals were used at Cambridge for the dHvA experiments.
2.We obtained an evidence suggesting the stripe structure in LNSCO similar to what has been reported by Tranquada et al.But we should be careful enough to wait for our definite conclusion until we know the influence of lattice imperfection on the structure. We succeeded in analyzing the lattice structure of SRO in detail, the result of which has been published in Physica C.
3.We could determine the Fermi surface for SRO from the dHvA experiment, which allowed us to discuss quantitatively the transport properties as well as the electronic speific heat. The result and discussion are published in four pieces of our recent papers.
4.We also obtained various new findings on the nonmetallic out-of-plane conduction, the splitting of the density of states near the Fermi level due to the 1/8 anomaly in LNBCO as well as on the possible p-wave pairing in SRO.