Study of intermediate magnetization states in deep submicrometer MRAM cells

The irregularities appeared in the R-H curves of MRAM cell were identified as caused by the existence of free layer magnetization vortex (type "V") and horseshoe (type "H") configurations. Both states can appear intermittently during repeat measurements and cause different types of MRAM write operation failure. Methods to reduce these states were proposed. The SAL-MRAM design can eliminate the vortex state at lower aspect ratio and thicker free layer than the conventional design.