In a conventional spin valve the shunt resistance of the pinning layer reduces the overall efficiency of the device. This problem has been overcome by using IrMn for the pinning layer at a thickness of about 20 Angstroms or less. For the IrMn to be fully effective it must be subjected to a two-step anneal, first in the presence of a high field (about 10 kOe) for several hours and then in a low field (about 500 Oe) while it cools. The result, in addition to improved pinning, is the ability to do testing at the full film and full wafer levels.