Micromagnetic study of pinning behavior in percolated media

摘要

A micromagnetic model has been developed describing the influence of the domain wall pinning in a magnetic thin film consisting of a granular micro structure with perpendicular magnetocrystalline anisotropy and a film thickness in the range of 5 -16 nm. The diameter of the prismatic domain wall pinning centers has been varied between 2 and 10 nm. The stability of a single written bit is investigated. Thermal stability (energy barrier = 80k_BT_(300)) can be guaranteed if the diameters of the pinning sites are equal or larger than the domain wall width and the film thickness is about 16 nm. For defects on the order of 6 nm magnetically very hard materials with values of K_u of 4 X 10~6 J/m~3 are required.