Patent ID: 6046139
Filing Date: 2000-04-04
Classification: C30B,Y10S

Abstract:
A method of making a large single crystal that is superconducting at temperatures at or below about 77.degree. K, comprising the steps of:a) mixing powders comprising from about 1-25 wt % Y.sub.2 BaCuO.sub.5, [211 YBCO], from about 0.05-1 wt % platinum, and the balance YBa.sub.2 Cu.sub.3 O.sub.7-x [123 YBCO] where x.ltoreq.0.6 so that the crystal is superconducting, the powders having an average particle size of about 5 micrometers or less;b) pressing the powders into a green powder compact having top and bottom surfaces,c) placing a seed crystal on the compact such that the seed crystal is oriented with a crystal plane of the crystal substantially parallel to the top surface of the compact;d) positioning the compact with the seed crystal on a bed of gravel consisting essentially of sintered YBa.sub.2 Cu.sub.3 O.sub.7-x and platinum;e) heating the compact to a temperature between about 1010-1050.degree. C. and holding the compact at the temperature for at least about 0.1 hour;f) cooling the compact at a rate such that YBa.sub.2 Cu.sub.3 O.sub.7-x crystal growth nucleates from the seed crystal; andg) cooling of the nucleated compact at about 0.1-1.degree. C. per hour to about 950.degree. C. such that the entire compact consists essentially of a single crystal YBa.sub.2 Cu.sub.3 O.sub.7-x grain nucleated from the seed crystal.