Magnetic anisotropy and reversal in epitaxial Fe/MgO(001) films

We investigate the magnetization reversal in Fe/MgO(001) films with fourfold in-plane magnetic anisotropy and an additional uniaxial anisotropy whose orientation and strength are altered using different growth geometries and postgrowth treatments. The previously adopted mechanism of 180°domain-wall nucleation clearly fails to explain the observed 180° magnetization reversal in Fe/MgO(001) films. We introduce a reversal mechanism with two successive domain-wall nucleations to consistently predict the switching fields of Fe/MgO(001) films for all field orientations with one set of values for domain-wall nucleation energies and uniaxial anisotropy.