The nucleation and reversal of magnetisation in high fields to form cylindrical domains in thin magnetic films

The critical fields for the nucleation and reversal of magnetisation in thin films leading to the formation of strip and bubble domain structures have been calculated. Attention has been paid to the role of imperfections which have been represented by a local lowering of the anisotropy constant. The value of the anisotropy constant and the size of the imperfections have been shown to be important and the corresponding fields compared with other important field values in bubble domain theory.