Fast switching in single-domain particles with uniaxial quartic anisotropy

The effect of quartic anisotropy on angular dependence of the high-speed switching behavior for uniaxial particles is studied. For large applied field angles with respect to the anisotropy axis, the magnetization reversal is dominated by the precessional switching and the switching speed is very fast in the presence of quartic anisotropy. The quartic anisotropy enhances the switching fields moderately, and expands the precessional switching regime towards the anisotropy axis, while slightly increases the switching time for the applied field magnitude larger than the anisotropy field. The angular dependence of switching field exhibits a broad minimum around the field angle of 45° for large quartic anisotropy. The results have implications for improving the recording characteristics of the tilted media.