Perpendicular magnetic tunnel junctions with the p-SAF structure having strong interlayer exchange coupling by the iridium spacer layer and their spin-transfer-torque switching properties

摘要

A perpendicularly magnetized magnetic tunnel junction (p-MTJ) is promising for a memory cell of spin-transfer-torque switching magnetic random access memory (STT-MRAM). For steady read and write operation of the cell, perpendicularly magnetized synthetic antiferromagnetic (p-SAF) coupling in the reference layer is one of the key technologies. So far, p-SAF with a Ru spacer layer has been intensively developed because of the high AF exchange coupling field (H_(ex)). Although there have been other candidates such as Ir and Rh besides Ru, they have not been extensively investigated yet. In this study, we systematically investigated magnetic properties of the p-SAF films with an Ir and Rh spacer layer. We also evaluated STT-switching properties in the p-MTJs with an Ir spacer layer.