Superconducting Oxides by the Sol-Gel Method Using Alkoxides

Abstract

The superconducting oxide Y-Ba-Cu-O has successfully been fabricated by the sol-gel method using Y, Ba, and Cu alkoxides as starting materials. Powders with specific surface area of 15 m2/g are prepared by this method. An X-ray diffraction pattern attributed to a 1-2-3 structure appears at 750°C and a bulk sample with Tc of 90 K is made by 900°C sintering in an oxygen atmosphere. A film of Tc=80 K with c-axis orientation is also fabricated using the sol-gel paste on an yttrium-stabilized ZrO2 substrate.

Bi–Sr–Ca–Cu–O superconducting films fabricated using metal alkoxides

“…3 ' 4 Therefore, there are some reports of the fabrication of Bi-Sr-Ca-Cu-O film using metal alkoxides, 5 " 7 as well as Y-Ba-Cu-O films. 8 " 14 The authors also reported that Cu alkoxide can be modified to increase its solubility by an OR-substitution reaction of the alkoxide with 2-dimethylaminoethanol in the preparation of In the case of Bi alkoxide, the preparation of a solution of Bi, Sr, Ca, and Cu alkoxides has been reported 5 " 7 but without discussion on the solubility increase of Bi alkoxide in this system. But it is difficult to prepare a homogeneous solution of Bi, Sr, Ca, and Cu alkoxides due to the insolubility of Bi and Cu alkoxides in common organic solvents.…”

High Temperature Ceramic Superconductors.

“…Processing speed is an extremely important economic consideration and hence must be significantly increased if high T, superconductor fibers are to see commercialization. [12] Numerous modified melt-texturing methods, such as the Quench-Melt-Growth, [13,14] the Melt-Powder-Melt-Growth, [15] and the Powder-Melt-Process [16] have been proposed. However, all these techniques have been developed to increase the flux pinning capability of YBa 2 Cu 3 07-, by finely distributing Y 2 BaCuO 5 .…”

“…to become so disordered that the model being used here i.o(a) = 7a e (12) is not useful, so one has a boundary defining the valid-(2a~ Iity limit for this model of Magnetic relaxation measurements have been made on two sets of samples of Y -.Pr_,BaCu 3 0 7 -6 high T, superconductors with 0<x 0. 10.…”

High-Temperature Ceramic Superconductors

“…The cutoff, free-space, and guide wave numbers are given by: From these fields, we can calculate the cavity's stored energy, U, the wall loss, P, and the resulting Q: where R s is the surface resistivity in ohms "per square," and the skin depth, 6 skin, is the e-folding distance for the rf wall currents into the imperfect conductor of conductivity 0.…”

“…' (5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16) at which point ps(w) approaches half that of unpinned flux. It increases further for higher frequencies until the flux is effectively completely unpinned; the analytic form of this increase depends on the shape of the pinning potential well.…”