In this work we employ macrospin simulations of the magnetization dynamics obtained from the Landau-Lifshitz-Gilbert equation coupled to angular momentum transport yielded by the nonequilibrium Green's function formalism to investigate two possible origins of the back-hopping effect in magnetic tunnel junctions with one layer of a synthetic antiferromagnet as reference layer. One possible origin discussed in this work is an additional sign reversal of the dampinglike (parallel) torque component as a function of the applied voltage. The other is the destabilization and switching of the reference layer by the spin-transfer torque. We find that this destabilization gives rise to a dynamic behavior manifesting in a back-and-forth switching of the free layer, while the sign reversal of the dampinglike torque results in a second hysteresis loop.

• Received 1 January 2023
• Revised 12 April 2023
• Accepted 12 April 2023

DOI:https://doi.org/10.1103/PhysRevB.108.014430

Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

Published by the American Physical Society