Columnar Defects and Scaling Behavior in Quasi 2D Type II   Superconductors
  Persistent scaling behavior of magnetization in layered high $T_c$ superconductors with short--range columnar defects is explained within the Ginzburg Landau theory. In the weak field region, the scaling function differs from that of a clean sample and both the critical and crossing temperatures are renormalized due to defects. In the strong field region, defects are effectively suppressed and scaling function, as well as critical and crossing temperatures are the same as in a clean superconductor. This picture is consistent with recent experimental results 
Gregory M. Braverman, Sergey A. Gredeskul and Yshai Avishai