K. M. Kojima

Reduction of Ordered Moment and Néel Temperature of Quasi-One-Dimensional Antiferromagnets Sr2CuO3 and Ca2CuO3

We report elastic neutron diffraction and muon spin relaxation ({mu}SR) measurements of the quasi-one-dimensional antiferromagnets Sr{sub 2}CuO{sub 3} and Ca{sub 2}CuO{sub 3}, which have extraordinarily reduced T{sub N}/J ratios. We observe almost resolution-limited antiferromagnetic Bragg reflections in Sr{sub 2}CuO{sub 3} and obtain a reduced ordered moment size of {approximately}0.06{mu}{sub B}. We find that the ratio of ordered moment size {mu}(Ca{sub 2}CuO{sub 3})/{mu}(Sr{sub 2}CuO{sub 3})=1.5(1) roughly scales with their N{acute e}el temperatures, which suggests that the ordered moment size of quasi-one-dimensional antiferromagnets decreases continuously in the limit of vanishing interchain interactions. {copyright} {ital 1997} {ital The American Physical Society}

Enhanced superconducting gaps in the trilayer high-temperature Bi2Sr2Ca2Cu3O(10+δ) cuprate superconductor.

S. Ideta, K. Takashima, M. Hashimoto, T. Yoshida, A. Fujimori, H. Anzai, T. Fujita, Y. Nakashima, A. Ino, M. Arita, H. Namatame, M. Taniguchi, K. Ono, M. Kubota, D. H. Lu, Z.-X. Shen, K. M. Kojima, S. Uchida Department of Physics, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan Graduate School of Science, Hiroshima University, Higashi-Hiroshima 739-8526, Japan Hiroshima Synchrotron Center, Hiroshima University, Higashi-Hiroshima 739-0046, Japan Photon Factory, Institute of Materials Structure Science, KEK, Tsukuba, Ibaraki 305-0801, Japan Department of Applied Physics and Stanford Synchrotron Radiation Laboratory, Stanford University, Stanford, CA94305 (Dated: May 8, 2009)

The electronic properties of cuprate ladder materials

Abstract We review the electronic properties of cuprate ladder materials, with a focus on so called ‘telephone number compound’ (Sr, Ca)14Cu24O41. This is the only ladder material which allows carrier doping and growth of single crystals. These features made investigations possible of transport anisotropy and frequency-dependent (optical) conductivity. One of the remarkable discoveries is the realization of superconductivity under high-pressure; however, analysis of transport dimensionality has suggested that the superconductivity is not due to Bose–Einstein condensation of singlet preformed pairs on the rungs, but due to cross-over from one- to two-dimensional electronic transport under pressure. This characterizes the superconductivity of 14-24-41 compound to be ‘anisotropic 2–d’, an extension of the category where high Tc cuprates belong to.

Muon spin relaxation studies of magnetic-field-induced effects in high-Tc superconductors

Muon spin relaxation measurements in high transverse magnetic fields [FORMULA: SEE TEXT] revealed strong field-induced quasistatic magnetism in the underdoped and Eu-doped (La,Sr)2CuO4 and La1.875Ba0.125CuO4, existing well above Tc and TN. The susceptibility counterpart of Cu spin polarization, derived from the muon spin relaxation rate, exhibits a divergent behavior towards T approximately 25 K. No field-induced magnetism was detected in overdoped La1.81Sr0.19CuO4, optimally doped Bi2212, and Zn-doped YBa2Cu3O7.

MAGNETIC BEHAVIOR IN LI-DOPED LA2CUO4

We report muon-spin-relaxation studies in the Li-doped cuprates La{sub 2}Cu{sub 1{minus}{ital x}}Li{sub {ital x}}O{sub 4} for {ital x}=0.01, 0.05, 0.10, 0.45, and 0.50. For low Li concentrations ({ital x}{le}0.10) we find a rapid suppression of {ital T}{sub {ital N}} as {ital x} increases, but little change in the magnitude and temperature dependence of the antiferromagnetic order parameter. This indicates that Li doping effectively destroys antiferromagnetism (similar to Sr doping, but different from Zn doping) without strongly affecting either the on-site Cu moments or the shape of the spin-wave excitation spectrum. For high Li concentrations we find that the majority of the sample volume is nonmagnetic, suggesting possible singlet-state formation. {copyright} {ital 1996 The American Physical Society.}

Expansion of vortex cores by strong electronic correlation inLa2−xSrxCuO4at low magnetic induction

The vortex core radius

In-plane optical conductivity of La 2 − x Sr x Cu O 4 : Reduced superconducting condensate and residual Drude-like response

{\ensuremath{\rho}}_{v},

Magnetic behavior in Li-doped La{sub {bold 2}}CuO{sub {bold 4}}

defined as the peak position of the supercurrent around the vortex, has been determined by muon spin rotation measurements in the mixed state of

Unconventional superconductivity in (TMTSF)2ClO4

{\mathrm{La}}_{2\ensuremath{-}x}{\mathrm{Sr}}_{x}{\mathrm{CuO}}_{4}

Electronic phase diagram of the two-leg ladder compound Sr14−xCaxCu24O41 as investigated by the transport property measurements

for