The effect of multiple defects on the energy barrier of magnetization reversal

The effect of multiple defects on the energy barrier of magnetization reversal in a one-dimensional magnetic nanowire is studied. By numerically solving the double Sine-Gordon equation via the finite-difference method, we obtain the energy saddle point through which the initial magnetic state jumps to the final ground states. The energy barrier which is defined as the difference between the energies of the saddle point and the initial states is calculated for various defect parameters. It is found that the energy barrier strongly depend on the number and distribution of the defects. For given defects, there exists an optimal distribution for a minimum energy barrier.