Switching characteristics of spin valve devices designed for MRAM applications

The low-frequency performance of spin valve giant magnetoresistive devices, designed for digital applications, has been examined as a function of device line width and aspect ratio. NiFe-Co-Cu-Co-NiFe-FeMn devices have been fabricated with line widths down to 0.4 mu m and aspect ratios that varied between 10:1 and 1.5:1. As the del ice line width decreases, the switching fields and switching field asymmetry increase due to magnetostatic effects. As the aspect ratio decreases, the switching field asymmetry increases rapidly and the devices become prone to domain noise. The experimentally observed switching behavior is compared to uniform rotation models to determine the accuracy with which the switching fields can be predicted. (C) 1999 Elsevier Science B.V. All rights reserved.