We have studied magnetic domain structure in (YSmLuCa)3(FeGe)5O12garnet thin film by using magnetic force microscopy (MFM). Domain wall contrast of bubble domains has been revealed using Permalloy–Fe double‐layer thin‐film tips. We have also observed that nanometer scale deformations of the surface disturb a magnetic bubble structure by introducing stripe domains. MFM images have shown that stripe domains pin their domain walls to surface scratches. The domains can change their location with respect to a scratch by switching a domain wall pinned to a scratch. ©1995 American Institute of Physics.