Theory for symmetric toggle magnetic random access memory

The authors analyze the critical switching curve for two identical coupled magnetic free layers, as used in toggle magnetic random access memory. The continuous and discontinuous transitions between different magnetic states are described. A general criteria for toggling is derived by summing up the number of clockwise and counterclockwise transitions, leading to a larger toggle region than previously reported. It also leads to a significant chirality effect, wherein the toggle region shifts depending on the order in which the word and bit line fields are applied. Finally, the authors discuss a type of switching useful for experimentally measuring the critical switching curve. © 2007 American Institute of Physics.