T. Tolinski, J. Baszynski

Anomalous Coercivity in Hysteresis Loops of
Antiferromagnetically Coupled Fe/Ag/Fe Trilayers on MgO(001) Substrates


A numerical simulation of the demagnetization process
(hysteresis loop) is performed in order to evaluate the bilinear and
biquadratic coupling in the
MgO/[Fe/Ag/Fe]/Ag trilayer. The proposed approach is
intermediate between the model assuming that the system always reaches the
Global Energy
Minimum (GEM) and the model considering the situation
when the system follows the Local Energy Minimum (LEM). The intermediate
approach is realized by
defining the energy barrier parameter Eb determining the
transition between the local energy minima. The value of Eb can be
obtained using reference
(uncoupled) samples. The numerical algorithm applied to
the GEM, LEM and the intermediate model is described. The bilinear J1 and
biquadratic J2 coupling parameters are determined from the ferromagnetic
resonance and hysteresis loop measurements.

phys. stat. sol. (a) 1998, 169, No. 1, 139-143