Materials and devices for reduced switching field toggle magnetic random access memory

Toggle magnetic random access memory (MRAM) has been proposed to solve the problems of small switching margins and half-select activated errors found in Stoner-Wohlfarth MRAM. However, it is widely acknowledged that the switching fields required for toggle MRAM are substantially larger than those needed for Stoner-Wohlfarth MRAM. Previously published reports on toggle switching use large toggle start fields around 75Oe. Here we examine, both experimentally and with a single-domain model, how both the toggle start and end fields vary with free layer intrinsic anisotropy, thickness, width, aspect ratio, and interlayer exchange coupling. By optimizing these parameters, we obtain 400nm width devices with toggle start fields below 30Oe.