Micromagnetic energy barrier calculations of percolated media for perpendicular recording

This paper investigates the influence of the thermal stability of the domain wall pinning in so-called percolation media consisting of a granular microstructure with perpendicular magnetocrystalline anisotropy and fully coupled grains with finite element micromagnetics. A continuous perpendicular media with random pinning sites is assumed and these sites are introduced by randomly placed non-magnetic cylinders with a diameter in the range of 2 nm to 8 nm. The density and the average distance between the pinning sites which is related to the diameter of the defects are varied between 4-8 nm. The film thickness is in the range of 5-16 nm. Also, the thermal stability of the domain wall pinning is investigated (energy barrier in kBT300) for two material parameter sets, (Js=0,7 T, K1=0,4 MJ/m3 and Js=1.2 T, K1=4 MJ/m3) with the exchange constant A in the range of 2.5-10 pJ/m.