Magnetic viscosity effects on the pinned layer loop of spin-valve materials

In this work, we report on measurements of magnetization with time [M(t)] around the pinned layer loop in spin-valve materials. These time-dependent effects are manifest via changes in M(t) in constant field (H) and via variations in the apparent coercivity with the sweep-rate of the applied field. The changes in the apparent coercivity on the pinned layer loop differ for the magnetizing and demagnetizing branches as does the form of M(t) data.