Effect of magnetic field on the electrical properties:

There are two principal geometries of the GMR effect, which are schematically shown in Figure 27.04. In the first case (Figure 27.04a), the current flows perpendicular to the multilayers (CPP geometry), whereas in the Figure 27.04b the current flows in the plane of the layers (CIP). The underlying physical mechanism is the same for both the CPP and CIP geometries.

Figure 27.04: (a) Current perpendicular to plane (CPP) and (b) current in plane (CIP) GMR geometries.