Lateral Exchange Spring Media

Lateral exchange spring media are a combination of percolation media and exchange spring media. A soft magnetic track is introduced that acts as a nucleation center during writing in a percolated media. Driven by the head field, the nucleated domains propagate in the hard magnetic data layer. A soft magnetic track with a width of 4 nm is sufficient to be able to write extremely hard materials such as FePt. The thermal stability of the bits in the data layer depends on the diameter and distance of the inclusion and the exchange constant. If the exchange of FePt can be reduced by a factor of two, thermally stable bits can be obtained with defects of about 3 nm in diameter