The switching behaviors of submicron magnetic tunnel junctions with synthetic antiferromagnetic free layers

The switching behaviors in elliptic shaped (aspect ratio=2) submicron magnetic tunnel junctions using CoFeB single free layer and CoFeB∕Ru∕CoFeB synthetic antiferromagnetic (SAF) free layers are studied. It is found that under considerable stray fields originating from pinned layers, junctions with single free layer show complex switching behaviors with larger Hc variations. In contrast, junctions with SAF free layers exhibit kink-free R‐H loops and less Hc variations. The Hc of junctions with SAF free layers is less dependent on the junction size than that with a single free layer. Furthermore, for junctions smaller than a critical size the SAF free layers have a smaller Hc than single free layers.