Domain structure in an ultrathin ferromagnetic film

The domain structure (DS) in an ultrathin ferromagnetic film is investigated. In the framework of a single approach, a small-amplitude (critical) DS with a smooth magnetization distribution as well as DS with a finite amplitude are described. The criterion of DS existence is obtained, and the domain size and DS amplitude are calculated for a wide range of film parameters. Existence of DS with out-of-plane magnetization in two intervals of the film thickness is predicted. Bulk and surface anisotropy constants are calculated by fitting of expressions to the experimental data.