Ultrasonic attenuation in the mixed state of high-Tc superconductors

Amplification of ultrasonic waves by a moving vortex structure

“…͑13͒ and ͑14͒ coincide with the Pankert's result. 7 We suppose at this point that coincides with the coefficient ⌫ Ϫ1 introduced by Pankert to describe the interaction of ultrasonic waves with vortices because of pinning in the TAFF regime. As seen from Eq.…”

“…[2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] Meanwhile it has been shown 2-6 that an ultrasonic wave can drag the vortex structure in the superconductors. This phenomenon has also been observed experimentally.…”

Vibrating sample experiments as a probe of anisotropic torque in YBCO single crystals

“…After early successes [1,2] in investigating vortex-pinsite interaction by ultrasound, interest in vortex research has focused on more intrinsic properties of the vortex system itself, because the intrinsically two-dimensional cuprate superconductors were seen to be nearly perfect model systems for studies of the peculiar properties of the repulsively ordered magnetic vortex ensemble in two dimensions with an intricate interplay between vortex-vortex interaction, vortex-pinsite interaction, fluctuations of the order parameter and thermal activation. Theoretical predictions (for a review, see [3]) for the behavior of magnetic vortex ensembles in two-dimensional superconductors with adjustable defect densities and high thermal activation energies called for experimental verification.…”

Transitions in the Vortex Lattice in YBa2Cu3OHucho1, Levy2 1996Phys. Rev. Lett.6010View full textAdd to dashboardCite

“…Ultrasonic experiments, probing as a thermodynamic quantity the elastic modulus, proved to be a useful tool for investigating the temperature-dependent depinning transition, since the modulations of the ionic lattice interact mainly with the pinned vortex system. Pankert showed [5] that the propagation of ultrasound in the mixed state is influenced by the elastic behavior of the vortex lattice as long as the vortex system is sufficiently pinned. These ideas were confirmed experimentally for superconductors with high pinning density [6,7].…”

“…These results have to be contrasted with the expected (and experimentally confirmed) field dependence of the attenuation in superconductors with a high density of pinning sites. Pankert showed [5][6][7] that ultrasonic attenuation in the thermally activated flux flow regime is proportional to the shear modulus of the vortex lattice, i.e., a~B 2 . That Pankert's model does not apply here may be interpreted as indication for the marginal role of vortex-pin-site interaction in our system at low fields.…”