Shear elastic properties of the Y_1−xPr_xBa₂Cu₃O_7-δsystem: A possible correlation betweenT_cand a structural instability

Abstract

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.

Mechanical Properties of Melt Textured Y1-xPrxBa2Cu3O7-δ Superconductor (x = 0.00 and 0.05)

“…The interest in the praseodymium-containing YBCO system dated from the 1990s, when studies had already demonstrated the dependence of elastic properties with temperature and the Pr amount in polycrystals 12 . Ivanov et al 13 studied elastic properties of granular Y 1−x Pr x Ba 2 Cu 3 O 7-δ with 0 > x > 0.45 (superconducting) and x = 0.65 (nonsuperconducting), employing an ultrasonic pulse-echo technique during heating from cryogenic temperatures to the room temperature. The shear velocity…”

“…They observed anomalies in the shear modulus concerning stoichiometry and temperature. The authors indicated that the study of single crystals could bring insights to explain the observed variations in elastic properties with the Pr concentration in the material 13 . The melt-texturing of REBCO arose as a possible technique for producing largegrain materials on an industrial scale, aiming at applications in engineering devices such as energy-storage systems and motors.…”