Computation of switching fields of stacked magnetic hexagonal particles with different heights

Switching fields of magnetic hexagonal particles with different heights, which were stacked in the easy axis direction, were investigated by computer simulation. The particles have easy axes perpendicular to their hexagonal planes. When the field is applied in the easy axis direction, the switching field of the stack is determined mainly by the end particle with the lowest switching field. On the other hand, when the field is applied in the hard axis direction, the switching field of the stack is mainly determined by the total height of the stack. The anisotropy field of a stack is also determined by the total height. The angular dependence of the switching field decreases with increasing number of stacked particles and with the total height of the stack. It also decreases when a small particle is stacked at one end of the stack.