Precessional switching on exchange biased patterned magnetic media with perpendicular anisotropy

We propose to use an in-plane exchange bias field to assist the applied field to obtain precessional switching of the magnetization in a high perpendicular anisotropy media. Our calculation is made in the limit of a nondamped macrospin particle. From the energy conservation, we derive the magnetic trajectories for any applied field magnitude and orientation. Precessional switching is shown to occur only for sufficiently large but not too high applied fields. The writing window associated with this switching field interval enlarges when the exchange bias field increases, as calculated quantitatively in the case of perpendicular recording. The potential application of this concept to magnetic recording is discussed. Compared to conventional media, the switching field distribution will be narrowed because the exchange bias provides a better immunity to texture dispersion. Since exchange bias reduces significantly the reversal field, we can use higher anisotropy materials and enhance the areal density while preserving the thermal stability. (C) 2005 American Institute of Physics.