1. Atoms on the direction of the ordering.
In nickel and iron atoms on the direction of the ordering is at lower temperatures, with a very short time to complete.The surface of the film and grain ral world there are many holes caused by defect.The thin film thickness, the surface area and grain boundary area and the volume ratio of the sum of, through the exchange of atoms and the cavity effect to accelerate the diffusion.The higher the hole concentration and diffusion rate of.
2. The ordering orientation of defects.
As mentioned earlier, defects in thin film concentration is high, the defects including impurity atoms, dislocation and holes.In the process of film formation, defects with high mobility.These defects and magnetization M, woe to cooperation.
Due to make M 'orderly deposition magnetic field orientation, also lead to orientational defects.After the external magnetic field deposition film, even if the film after removing deposition magnetic field, remained orientational defects.Theory has been proved that a pair of adjacent defects with M, maintain lower energy when it is parallel to the orientation, this leads to defects of directional arrangement, thus establish a uniaxial anisotropy.