Energy barriers for magnetization reversal of partially exchange-coupled particles

We study the magnetization reversal of a two-particle system with partial exchange coupling. We assume that the particles are discs and that the exchange coupling occurs through one of their plane faces extending up to 5lw into each particle (lw=(A/K)1/2). The easy axis of particle 1 coincides with the direction of the applied magnetic field H and the one corresponding to particle 2 is such that both easy axis are parallel to the contact face.