Orientational states of magnetization in epitaxial (1 1 1)-oriented iron garnet films

A (1 1 1) oriented single-crystal iron garnet film having mixed cubic and uniaxial anisotropy was investigated. Taking into account the first two constants of cubic anisotropy an expression for anisotropic part of free energy was derived in the polar coordinate system connected with films crystallographic directions. Its minimization allowed to obtain possible orientational phases. While only the first cubic anisotropy constant is taken into account, there are a symmetric phase of `easy axis' anisotropy and two angle phases with `easy cone' anisotropy. By adding the second cubic anisotropy constant into consideration one more symmetric phase may be found that correspond to `easy plane' type of anisotropy. Orientation of easy magnetization directions are analyzed as well as their influence on domain structure configurations.