An apparatus for studying the attenuation of high frequency ultrasonics in superconductors

Anomalous attenuation of longitudinal ultrasound in the intermediate state of pure type I superconductor

“…This is all the more correct, because the shape of curves Г(H) after the one and two revolutions by the magnetic field H are similar in Fig. 2., and the value of ultrasound absorption Г at each point after the two revolutions is practically independent of the number of revolutions 5) . The intermediate state regions with the small and big concentrations of the N phase with the probably present isolated filaments of the N and S phases and without the periodicity of the IS structure are characteristic.…”

“…1. We present some experimental results, obtained at the research on the longitudinal ultrasound absorption in an intermediate state of the high pure Ga single crystal at the frequency of 50 -190 MHz, using the impulse method 2) [5]. The measurements were conducted in a cryostat, using the absorption pumping-off of the vapor of ~25 cm 3 of the liquid Helium ( 3 He) at the temperatures down to 0.32°K [6].…”

“…The axis of the cylinder coincided with the crystallographic axis b of the high pure Ga single crystal and with the ultrasound propagation direction of k 3) . The measurements of ultrasound absorption dependence Г(H) were conducted by the relative method, comparing the propagated signal impulse with the standard impulse [5] in the regime of automatic plotting on the PDS-021 x-y recorder. The plates of X-cut quartz with the thickness of 0.3 mm and the diameter of 4.5 mm were used as the converters of the high frequency signal into the ultrasound (and viceversa); it is necessary to note that the monochromatic beam of longitudinal ultrasound propagated along the central region of sample without the interaction with the side surfaces of a sample 4) .…”