Magnetic anisotropy and reversal in epitaxial Fe/MgO(001) films   revisited
  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 tuned using different growth geometries and post growth treatments. The previously adopted mechanism of 180^{o} domain wall nucleation clearly fails to explain the observed 180^{o} magnetization reversal. A new reversal mechanism with two successive domain wall nucleations consistently predicts the switching fields for all field orientations. Our results are relevant for a correct interpretation of magnetization reversal in many other epitaxial metallic and semiconducting thin films. 
Qing-feng Zhan, Stijn Vandezande, Kristiaan Temst, and Chris Van   Haesendonck