Glass Formation of High-Tc Compound BiCaSrCu₂Ox by Rapid Quenching

A new high T c compound, BiCaSrCu 2 O x , was successfully prepared in glassy form by a twin-roller quenching method for the first time. The rapidly quenched glass has a glass transition temperature of 390°C and a crystallization temperature ( T x ) of 444°C. Heat-treatment at higher temperatures above T x increased the crystallinity and at 850°C produced X-ray patterns identical to those of the starting compound. The resistivity of the sample heat-treated at 850°C shows the onset T c at 88 K. These findings are expected to facilitate fiber drawing for such high T c compounds.