210 K ultrasonic and specific heat anomalies in the (Bi sub 0. 85 Pb sub 0. 15 ) sub 2 Sr sub 2 Ca sub 2 Cu sub 3 O sub 10+x superconductors

Ultrasonic study on single phase (Bi{sub 0.85}Pb{sub 0.15}){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub 10 + x} revealed that there are isothermal-like anomalies near 210 K in both velocity and attenuation of longitudinal and transverse sound waves. Specific heat measurements also showed clear anomaly at about 210 K, suggesting the occurrence of some structural changes or phase transition. Comparing with YBa{sub 2}Cu{sub 3}O{sub 7 {minus}y}, possible mechanisms are discussed.