Method for Simultaneously Enhancing the Transition Temperature and IncreasingMechanical Strength of Yttrium Barium Copper Oxide (YBa2Cu4O8)

摘要

Y124 can be heated to 850 deg C without serious O2 loss, and also Y123 loses O2from its structure at temperatures above 400 deg C. Partial substitution of Ca for Y and of Li for Cu raised the transition temperature and enhanced sintering in Y1Ba2Cu4O8. We measured the critical temperature by two methods: a microwave technique (RF) which measures the surface resistivity at 35 GHz; and an AC technique which measures the magnetic screening provided by the whole sample. Twelve samples of Y124 or Y1-zCazBa2Cu4-xLixO8 were prepared; a summary is presented. (AN).