A computational and experimental study of exchange coupling in FePt self-organized magnetic arrays

A study of the magnetic properties of self-organized magnetic arrays of FePt particles has been carried out. Experimental measurements of the magnetic properties are compared with the results of a computational model taking into account the magnetostatic and exchange coupling between the particles. The magnetostatic coupling is found to be very weak, but the experimental data cannot be explained without the existence of strong exchange coupling between the particles, believed to result from the sintering of the particles during the annealing process. The best fit of the theoretical calculations to the experimental data suggests that after high temperature annealing values of K close to the bulk value can be obtained.