
400 Nanosensors: Physical, Chemical, and Biological
ferromagnetic layers are antiparallel (Figure 7.1a), while in the latter case,
they become parallel (Figure 7.1b). Here, the current ows parallel to the
planes of the layers. Figure 7.1c and d represents the situation for current
owing perpendicular to the planes of layers.
The change in the resistance of the multilayer arises when the applied eld
aligns the magnetic moments of the successive ferromagnetic layers, as is
illustrated schematically in Figure 7.2. When the eld is absent, the magnetic
moments (the torque exerted on a magnet within a magnetic eld) are anti-
parallel (Figure ...