  We consider the effects of impurities on the enigmatic hidden order (HO)
state of the heavy-fermion material URu2Si2. In particular, we focus on local
effects of Rh impurities as a tool to probe the suppression of the HO state. To
study local properties we introduce a lattice free energy, where the time
invariant HO order parameter "psi" and local antiferromagnetic (AFM) order
parameter M are competing orders. Near each Rh atom the HO order parameter is
suppressed, creating a hole in which local AFM order emerges as a result of
competition. These local holes are created in the fabric of the HO state like
in a Swiss cheese and "filled" with droplets of AFM order. We compare our
analysis with recent NMR results on URu2Si2 doped with Rh and find good
agreement with the data.
