We employed a scanning Hall probe microscope to detect the hopping of individual vortices between pinning sites along grain boundaries in thin films in the presence of an applied current. Detecting the motion of individual vortices allowed us to probe the current-voltage characteristics of the grain boundary with voltage sensitivity below a femtovolt. We find a very sharp onset of dissipation with with an unprecedented high exponent of that shows essentially no dependence on temperature or grain boundary angle. Our data have no straightforward explanation within the existing grain boundary transport models.
Dynamics of single vortices in grain boundaries: characteristics on the femtovolt scale
B. Kalisky, J. R. Kirtley, E. A. Nowadnick, R. B. Dinner, E. Zeldov, Ariando, S. Wenderich, H. Hilgenkamp, D. M. Feldmann, K. A. Moler; Dynamics of single vortices in grain boundaries: characteristics on the femtovolt scale. Appl. Phys. Lett. 18 May 2009; 94 (20): 202504. https://doi.org/10.1063/1.3137164
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