Read Back Signals in Magnetic Recording - Research Group Fidler

FEM Simulations
Magnetic Material Js [T] K1 [J/m 3 ] A [J/m] Hex [T] Α
Free Layer 1 0 1.3E-11 0 0.1 *
Pinned Layer 1.885 0 1.2E-11 0.05 *
0.1 *
Hard Bias 1 2.5E5 1.3E-11 0 0.1 *
Shields 1 0 1.0E-11 0 0.1 *
Table 6.1: The values of the spontaneous polarization, the anisotropy constant, the
exchange constant, and the antiferromagnetic exchange coupling field, and the Gilbert
damping constant, which are assumed for our magnetic model. The asterisk-marked values
are valid unless otherwise noted.
6.1.2 Conductor Model
For the current model we have to consider all conductive parts of the model. This also
includes the antiferromagnet or capping layers. The conductor model is shown in Figure 6.2.
However, only the most important layers are taken into account for our simulations. So we
neglect the thin capping layers, although they make a minor contribution to the conductance.
Thus our conductor model contains the free layer, pinned layer, nonmagnetic spacer layer
(Cu), the antiferromagnetic layer, and parts of the leads.
Figure 6.2: The FEM conductor model is shown. This simplified model shows the four
main layers of a GMR element, which contribute most to the conductance: The free layer
(dark blue) the nonmagnetic Cu layer (orange), the pinned layer (light blue), and the
antiferromagnet (yellow). Additionally the high conductive leads (pink) are shown.
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y
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