Effect of Ba-site substitution by Sr on ultrasonic velocity and electron–phonon coupling constant of DyBa2−xSrxCu3O7−δ superconductors

Effects of Cd2+ substitution on elastic properties and step-like anomalies in Tl0.9Bi0.1Sr1.8Yb0.2Ca1−Cd Cu1.99Fe0.01o7− superconductors

“…Similar result was reported for Al 3 þ substituted EuBa 2 Cu 3 O 7 À δ [16], which showed λ increased with increasing Al 3 þ . In contrast, Sr substitution in DyBa 2 À x Sr x Cu 3 O 7 À δ [17] and Zn substitution in ErBa 2 Cu 3 O 7 À δ [42] showed decrease in electron-phonon coupling constant, λ BCS value.…”

“…The experimental data of all samples for the present investigation both below and above the temperature of the elastic anomaly, T A was fitted to Eq. (17). The open circles represent the experimental data and the solid lines represent the theoretical fitting.…”

“…This model is used to illustrate the extent of deviation of velocity or elastic moduli from the calculated anharmonicity curves at high temperatures. Previous works [14,16,17] such as for DyBa 2 À x Sr x Cu 3 O 7 À δ have shown that sound velocity in high temperature superconductors is dominated by lattice anharmonicity at lower temperatures but deviated at higher temperatures. A comparison between measured sound velocity data and calculated anharmonicity curve indicates that the appearance of step-like elastic anomalies at higher temperatures influenced the deviation of experimental data from calculated anharmonicity curves.…”

“…On the other hand, a number of studies have used Lakkad's anharmonicity model to explain and estimate the temperature dependence of velocity behavior or elastic moduli of RE123 and Tlbased systems [14][15][16][17][18]. This model is used to illustrate the extent of deviation of velocity or elastic moduli from the calculated anharmonicity curves at high temperatures.…”

A Study of Temperature Effect on the Rayleigh Velocity of Superconductor Material Type Bi2212 Using Acoustic Techniques

“…The scanning acoustic microscopy developed by Quate et al [3,4] is the one among the non-destructive characterization techniques widely used for determining both the elastic proprieties of a material and their different propagation speed such as longitudinal (V L ), transversal (V T ), and Rayleigh velocities (V R ). Since this technique has been used for characterizing various superconductor compounds [5][6][7][8][9][10], therefore, our study was devoted to carry out the modelling of the acoustic signature V(z) and the reflection coefficient R(θ), in case of porous and non-porous superconductor compound type Bi2212, in order to determine the evolution of the velocity of wave surfaces (Rayleigh velocity) as a function of temperature.…”