Magnetic behavior of partially exchange-coupled particles

A system of particle pairs with partial exchange coupling is studied, considering identical particles and a fixed angle between their anisotropy axes. The energy of each pair is calculated in terms of the extent of interaction, β, as a function of the applied demagnetizing field. Using the probability per unit time for the inversion of magnetization, the coercive field Hc and the viscosity S of the system are calculated. An unexpected result is that fully coupled particles are more stable against temperature than the uncoupled particles.