Ichiro Tsukada

Spin-Vacancy-Induced Long-Range Order in a New Haldane-Gap Antiferromagnet

Magnetic susceptibility, high-field magnetization, and inelastic neutron scattering experiments are used to study the magnetic properties of a new S=1 quasi-one-dimensional antiferromagnet PbNi{sub 2}V {sub 2}O{sub 8} . Interchain interactions are shown to be almost, but not quite, strong enough to destroy the nonmagnetic singlet ground state and the energy gap in the magnetic excitation spectrum. Substituting nonmagnetic Mg{sup 2+} (S=0 ) ions for Ni{sup 2+} (S=1 ) induces a magnetically ordered state at low temperatures. To our knowledge this is the first observation of doping-induced long-range order in a Haldane-gap system. {copyright} {ital 1999} {ital The American Physical Society }

A Novel Heavy-Fermion State in CaCu3Ru4O12

We have measured the susceptibility, specific heat, resistivity, and thermopower of CaCu 3 Ti 4- x Ru x O 12 and CaCu 3- y Mn y Ru 4 O 12 , and have found that CaCu 3 Ru 4 O 12 can be regarded as a...

Structural Phase Transition and Metallic Behavior in Misfit Layered (Bi,Pb)-Sr-Co-O System.

The crystal structure of Bi2-xPbxSr2Co2Oy has been investigated by X-ray diffraction and electron diffraction analyses. In contrast to what has previously been considered a Bi2Sr2CaCu2O8-type structure, we found that this material has a misfit layer structure: two subcells with different periodicities are alternately stacked. We have studied the x dependence of the crystal structure and found a discontinuous phase transition at x 0.2, where only Bi-Sr-O layers show a drastic change in lattice constants. Pb doping induces metallic behavior, but the effect of the structural phase transition is less clearly observed, which indicates that the electronic properties are mainly dominated by CoO2 layers.

Systematic Comparison of Eight Substrates in the Growth of FeSe0.5Te0.5 Superconducting Thin Films

We have investigated the crystal structures and superconducting properties of thin films of FeSe0.5Te0.5 grown on eight different substrates. Superconductivity is not correlated with the lattice mismatch; rather it is correlated with the degree of in-plane orientation and with the lattice parameter ratio c/a. The best superconducting properties were observed in films on MgO and LaAlO3 (Tczero of 9.4 K). Transmission electron microscopy observation showed that the presence or absence of an amorphous-like layer at the substrate surface plays a key role in determining the structural and superconducting properties of the grown films.

Epitaxial Growth of FeSe0.5Te0.5 Thin Films on CaF2 Substrates with High Critical Current Density

In-situ epitaxial growth of FeSe

Superconductivity of Bi2Sr2Can−1CunOy (n=2, 3, 4, and 5) thin films prepared in situ by molecular‐beam epitaxy technique

_{0.5}

Ferromagnetism and large negative magnetoresistance in Pb doped Bi-Sr-Co-O misfit-layer compound

Te

Two-stage spin-flop transitions in the S = 1/2 antiferromagnetic spin chain BaCu(2)Si(2)O(7).

_{0.5}

Superconductivity of FeSe0.5Te0.5 Thin Films Grown by Pulsed Laser Deposition

thin films is demonstrated on a non-oxide substrate CaF

Epitaxial Growth of Bi-Sr-Ca-Cu-O Thin Films by Molecular Beam Epitaxy Technique with Shutter Control

_2