A low temperature device for magneto-acoustic studies

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

“…Although the general picture of phenomena is complicated, the scale of the effect is striking, it make sense to note that the magnitude of certain oscillations exceeds the magnitude of total ultrasound absorption Г 0 in the normal metal at the magnetic field equal to the critical magnetic field H = H c ! As shown by the computer modeling, at k a ~ 3-30 and a/D ext ~ 0.1-0.9, the scale of the real phenomenon is well described by the theory 7) . It is necessary to take into consideration that the experimental results may differ from the theoretical predictions, because the theory employed a model of superconductor with the very simple Fermi surface.…”

“…The vector H could be rotated in the plane of the axes a and c of the high pure Ga single crystal, which is perpendicular to the axis of a sample, at a rate of 1 rev/min. The stabilization of the magnetic field H (and, when necessary, the change of the magnitude of magnetic field H in accordance with the linear law) was achieved by the magnetic fieldstabilization and magnetic field -sweep schemes [7] with the stabilization accuracy better than 3x10 -4 . During the course of the measurements, the sample was in direct contact with the liquid 3 He, and the earth's magnetic field was compensated by the means of the two pairs of the Helmholtz coils.…”