Switching Dynamics for an Interacting Anisotropic Dipole Pair of Arbitrary Bond Angle

The switching dynamics for a pair of identical uniaxially anisotropic dipoles of arbitrary bond angle is calculated for the case of the applied field coincident with the common anisotropy axis. Recently, we presented the nucleation fields (as a function of bond angle and interaction strength) which were derived by following the system quasi-statically from initial saturation to the first unstable equilibrium. Here, with these fields as initial conditions, we use the dynamic Gilbert equations to follow the precession of the moments to a stable equilibrium state. For the two possible final configurations, parallel or nearly antiparallel moments, an interaction strength-bond angle plot gives regions where these states are accessible. These regions are only moderately dependent on interaction strength. For small bond angles (with respect to the anisotropy direction) the moments rotate incoherently to the low-energy parallel state. For large bond angles the moments are constrained to rotate coherently to the parallel state. At intermediate bond angles the moments rotate incoherently to a stable antiparallel state. These conclusions are found to be independent of the dynamic damping parameter.