Irreversible magnetization processes in a soft magnetic platelet

The influence of an applied field on the magnetic domain structure of a per malloy platelet (3.2 mu m x 1 mu m x 80 nm) is studied by means of micromag netic finite element modeling. Starting from two different demagnetized dom ain states with nearly closed flux, a magnetic field is applied in-plane an d increased stepwise. The magnetization process is determined by the motion of domain walls and domain structure conversion. Irreversible processes oc cur when 180 degrees walls intersect an edge of the sample or when two doma in walls cancel each other. A repetitive repositioning of the discretizatio n points is used to both avoid numerical grid pinning effects and to reduce discretization errors. The numerical results compare favorably with experi mental observations. (C) 2000 Elsevier Science B.V. All rights reserved.