Disorder induced power-law response of a superconducting vortex on a   plane
  We report drive-response experiments on individual superconducting vortices on a plane, a realization for a 1+1-dimensional directed polymer in random media. For this we use magnetic force microscopy (MFM) to image and manipulate individual vortices trapped on a twin boundary in YBCO near optimal doping. We find that when we drag a vortex with the magnetic tip it moves in a series of jumps. As theory suggests the jump-size distribution does not depend on the applied force and is consistent with power-law behavior. The measured power is much larger than widely accepted theoretical calculations. 
N. Shapira, Y. Lamhot, O. Shpielberg, Y. Kafri, B. J. Ramshaw, D. A.   Bonn, Ruixing Liang, W. N. Hardy, and O. M. Auslaender
cond-mat.supr-con cond-mat.dis-nn cond-mat.mes-hall cond-mat.soft cond-mat.stat-mech