Nanostructure of magnetic monopole defects

Nanoscale structure of the magnetic induction at monopole defects in artificial spin-ice lattices.
C. Phatak, A. K. Petford-Long, O. Heinonen, M. Tanase, and M. De Graef
Phys. Rev. B 83, 174431 (2011)

Magnetic induction color maps reconstructed after (a) the first demagnetization cycle, showing the formation
of defect strings and two magnetic monopole defects, and (b) after the second demagnetizing loop.