Generating strong magnetic flux shielding regions in a single crystal of   Bi2Sr2CaCu2O8 using a blind hole array
  Magneto-optical imaging studies in a single crystal of Bi2Sr2CaCu2O8 partially patterned with a hexagonal array of pinning centers (blind holes) reveals local features in the patterned region which are distinct compared to the pristine unpatterned regions in the sample. The patterned area exhibits a strongly diamagnetic local magnetization response and is characterized by a local penetration field enhanced by a factor of three. We show that strong shielding currents around the periphery of the nanopatterned region create a barrier which prevents vortex entry into the patterned region thus sustaining an effectively flux-free state upto the enhanced penetration field. 
Gorky Shaw, Biplab Bag, S. S. Banerjee, Hermann Suderow, and T.   Tamegai
cond-mat.supr-con cond-mat.mtrl-sci