International Business Machines Corporation
MULTILAYERED MAGNETIC FREE LAYER STRUCTURE FOR SPIN-TRANSFER TORQUE (STT) MRAM

Abstract:

A multilayered magnetic free layer structure is provided that includes a first magnetic free layer and a second magnetic free layer separated by a non-magnetic layer in which the second magnetic free layer has a lower perpendicular magnetic anisotropy field, H.sub.k, as compared with the first magnetic free layer. The multilayered magnetic free layer structure of the present application substantially reduces the switching current needed to reorient the magnetization of the two magnetic free layers. The lower H.sub.k value of the second magnetic free layer as compared to the first magnetic free layer improves the switching speed of the second magnetic free layer and thus reduces, and even eliminates, write errors.