Large, thin‐film single domain areas have been observed, in the absence of a bias field, in garnets with magnetization perpendicular to the film plane.1,2The domain stability in the work by Krumme1was attributed to a combination of low saturation magnetization and a low Curie temperature. Uchishiba2relates the stability in his double layer system to appropriate anisotropy fields in one layer compared to the magnetization in the other layer. A more complete model for large domain stability in a bias field free environment is given in this work. Three distinct stability regimes are predicted by the model and all have been observed experimentally. Areas 3.5‐cm in diameter have been made into stable single domains. This was achieved in a material showing a zero bias strip width of 4.5 &mgr;m. The single domain diameter was, therefore, 7500 times the equilibrium energy domain width. The technique developed and the model have led to a new means for observing magnetic defects. More importantly, it also offers a means for measuring the strength of the defects. Possible applications of the model are also discussed.