C.H. Back et al., page1 Minimum Field Strength in Precessional Magnetization Reversal

Ultrafast magnetic field pulses as short as 2 ps are able to reverse the magnetization in thin in-plane magnetized cobalt films. The field pulses are applied in the plane of the film and their direction encompasses all angles with the magnetization. At right angle to the magnetization maximum torque is exerted on the spins. In this geometry a precessional magnetization reversal can be triggered by fields as small as 184 kA/m. Applications in future ultrafast magnetic recording schemes can be foreseen. C.H. Back et al., page3 Based on experimental advances, magnetization reversal has undergone considerable development in recent years. For instance, it is now possible to observe the direction of the magnetization in nanosized single-domain particles (1-3). In such experiments static magnetic fields are applied. The probability that the magnetization M will reverse is determined as a function of the angle at which the external magnetic field exH is applied to the particle. The reversal mechanism is difficult to understand in detail because