Magnetoresistance of a 2-dimensional electron gas in a random magnetic   field
  We report magnetoresistance measurements on a two-dimensional electron gas (2DEG) made from a high mobility GaAs/AlGaAs heterostructure, where the externally applied magnetic field was expelled from regions of the semiconductor by means of superconducting lead grains randomly distributed on the surface of the sample. A theoretical explanation in excellent agreement with the experiment is given within the framework of the semiclassical Boltzmann equation. 
Anders Smith, Rafael Taboryski, Luise Theil Hansen, Claus B. Sorensen,   Per Hedegard and P. E. Lindelof (Niels Bohr Institu...