Ultrasonic strain effects on Bi2223 cuprate superconductors

Abstract

It has been well known that the stability of the superconducting state against thermal fluctuation can be manipulated by applying static strain such as that produced by either stretching or squashing. We have succeeded in manipulating the Meissner signal of a typical cuprate superconductor Bi2Sr2Ca2Cu3Ox (termed Bi2223) with a dynamical stress of 1 MHz frequency, generated by a piezoelectric device. The magnitude of the superconducting transition temperature (Tc) shift observed there exceeds one hundred times as much as those under static strain. We consider that the acoustic stress induces dynamic perturbation toward the lattice, resulting in the suppression of the formation of Cooper pairing.

Effect of ultrasonic strain on p-type silicon wafers

“…Figure 5 shows the time dependence of the electrical resistance of the p-type silicon while repeating between OFF and 20 V pp at 180 K. The time resolution of the measurement of the resistance was 0.2 s. When we lowered the applied voltage from 20 V pp to OFF, the resistance exhibited an increase of approximately 400 ³ within less than 0.2 s. When we applied a voltage of 20 V pp again, the resistance recovered to the initial value within less than 0.2 s. This response speed is faster than that of a manipulation of the phase transition, such as moving from an ordered state to a non-ordered one. 18) Finally, we state the effect of heating by applying a voltage to the acoustic device. Indeed, the monitored temperature of the sample space deviated from the actual temperature of the sample, and the deviation increases with the applied voltage.…”