Interacting nanopatterned pins: barriers towards creating interstitial   vortices
  We show that by nano-patterning a superconductor (NbSe2 single crystal) with an array of blind holes produces significant magnetic field sweep rate dependent metastable magnetization response. Our results are explained on the basis of a unique collective action of the blind holes pins which creates a barrier against vortex redistribution inside the sample. We propose that this barrier leads to a phase separation creating distinct population of vortices viz., those pinned on blind holes and those confined in the interstitials between the holes. 
Gorky Shaw, Shyam Mohan, Jaivardhan Sinha and S. S. Banerjee