Michiaki Matsukawa

Anisotropic Thermal Diffusivity and Conductivity of YBCO(123) and YBCO(211) Mixed Crystals. II

The anisotropic thermal diffusivity α of the highly c-axis-oriented Y–Ba–Cu–O bulk superconducting crystals has been measured quasi-simultaneously with the thermal conductivity κ. The estimated values of the specific heat C by use of α and κ values parallel and perpendicular to the c-direction agreed with each other. In these crystals prepared by the modified melt texture growth (MMTG) method, fine Y2BaCuO5 particles are dispersed in the YBa2Cu3O7-x superconducting matrix phase. Based on a simple model, the thermal diffusivity and the specific heat of the YBa2Cu3O7-x matrix phase are separated using independently measured data of a Y2BaCuO5 polycrystal. The influence of Y2BaCuO5 particles on the thermal properties of the mixed crystals is discussed.

Low thermal conductive Bi-2223 tapes sheathed with Ag-Au alloys

With the view of applying to power current leads for superconducting magnet systems and for other cryogenic power handling systems, low thermal conductive Bi-2223 superconducting tapes sheathed with Ag-Au alloy were fabricated and their thermal conductivities were measured from 12 to 260 K. The critical current density (overall-J/sub c/) was about 1700 A/cm/sup 2/ at 77 K, 0 T and remained nearly constant irrespective of Au concentration up to 11 at.%. The tape sheathed with Ag+11 at.%Au alloy, of which the superconductor cross-section ratio f/sub sc/ was 0.65, had a thermal conductivity value about 0.2 W/cmK at 77 K this value is as low as that of Cu-Zn. It was found that the thermal conductivity of the tape was close to the calculated one based on f/sub sc/ and the independently measured thermal conductivities of the Ag-Au alloy acid the Bi-2223 superconductor. The superconducting tapes sheathed with the alloy were confirmed to be suitable for the application as power current leads. >

Effect of pressure on the magnetic, transport, and thermal-transport properties of the electron-doped manganite CaMn_{1-x}Sb_{x}O_{3}

We have demonstrated the effect of hydrostatic pressure on magnetic and transport properties, and thermal transport properties in electron-doped manganites CaMn

Effect of suppression of local distortion on the magnetic, electrical, and thermal transport

_{1-x}

Anomalous lattice distortion in Pr-substituted double-layered Perovskite manganite La1.2Sr1.8Mn2O7 single crystals: II

Sb

Heavily cold worked high-purity Ta as a reinforcing stabilizer

_{x}

Anisotropic phonon conduction and lattice distortions in colossal-magnetoresistance bilayer manganite (La1-zPrz)1.2Sr1.8Mn2O7 (z=0, 0.2, 0.4, and 0.6) single crystals

O

Thermal conductivity of Ag-doped Bi-2212 superconducting materials prepared by the floating zone method

_{3}

Development of a 50 A-fast response, magnetically controlled persistent current switch

. The substitution of Sb

Current-induced nonlinear conduction of two-electron doped manganites Ca1-xCexMnO3

^{5+}