Spin-valve and pseudo-spin-valve device switching for giant magnetoresistive random access memory applications

Previous work has described the performance of current-in-plane (CIP) pseudo-spin-valve (PSV) devices for giant magnetoresistive random access memory (GMRAM) applications for 1R0T GMRAM architectures based on a bit cell containing a GMR resistor and no transistors. Device characteristics are reported here of CIP spin-valve (SV) and PSV devices that can be applied to GMRAM two-resistor/two-transistor (2R2T) latch memory architectures. As a function of hard-axis in-plane bias field, the PSV and SV devices have switching field and dR dependencies that are opposite in sign, which indicate differences in the magnetization reversal process between PSV and SV devices. For easy-axis fields that exceed the storage layer switching field but are less than the pinned-layer reversal field, PSV devices have two layers that respond to applied fields while SV devices have a single layer that responds. The PSV device, therefore, shows an additional effect of mutual magnetization coupling between the two magnetic layers, while the SV device acts more simply, as a biased single layer.