The shear elastic behaviour of the granular Y I -~P T~B~~C U~O~-~ system with x=O; 0.1; 0.15; 0.2; 0.3; 0.45 (superconducting) and 0.65 (nonsuperconducting) has been studied by a mechanical resonance method. Anomalies of shear ultrasonic velocity were found at the superconducting transition temperature TJx) and at two temperatures Tl(x) and T~( x ) above T,. The lower one of these at the temperature Tl(x) is observed only in the superconducting samples. For Pr-substituted samples Tl(x) corresponds to the onset of elastic softening during cooling. The third anomaly was found at a temperature T~( x ) closer to room temperature. The dependencies of T,, T I and T2 on x werc determined. The results indicate a correlation between T,(x) and Tl(x). A possible similarity to the A-15 compounds is discussed.
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