Vortex bending and avalanche in a type-II superconductor observed with contactless ultrasonics

Katsuhiro Kawashima
1998 Physical Review B (Condensed Matter)  
Severe vortex bending as large as 90°and giant avalanche were observed over a large area of a disk-shaped type-II superconductor in the mixed state using a contactless ultrasonic technique. This phenomenon is greatly different from a conventional critical state model in which the vortices are assumed to stand perpendicular to the disk plane. Equations describing the contactless ultrasonics are derived using a dynamic equation of vortex motion that takes account of crystal displacements arising
more » ... rom ultrasonic wave propagation. Using the equations and the ultrasonic data, the variations of the bending angle and the vortex densities are obtained as a function of applied magnetic field.
doi:10.1103/physrevb.58.490 fatcat:p4v4zewq7rebplythap4f674eq