2017/05/03 by B. Lacoste, M. Romera, Lacoste, Bertrand +5
Biochemistry, Genetics and Molecular Biology · Physics and Astronomy · #Applied Physics (physics.app-ph) #Electron Spin Resonance Studies #FOS: Physical sciences #Magnetic properties of thin films #Other Condensed Matter (cond-mat.other) #Quantum and electron transport phenomena
paper · pdf · doi:10.48550/arxiv.1705.01335
openalex publication_date 2017/05/03 · openalex created_date 2017/05/12 · openalex updated_date 2026/07/28
The non-linear parameters of spin-torque oscillators based on a synthetic ferrimagnet free layer (two coupled layers) are computed. The analytical expressions are compared to macrospin simulations in the case of a synthetic ferrimagnet excited by a current spin-polarized by an external fixed layer. It is shown that, of the two linear modes, acoustic and optical, only one is excited at a time, and therefore the self-sustained oscillations are similar to the dynamics of a single layer. However, the non-linear parameters values can be controlled by the parameters of the synthetic ferrimagnet. With a strong coupling between the two layers and asymmetric layers (different thicknesses), it is demonstrated that the non-linear frequency shift can be reduced, which results in the reduction of the linewidth of the power spectral density. For a particular applied field, the non-linear parameter can even vanish; this corresponds to a transition between a red-shift and a blue-shift frequency dependence on the current and a linewidth reduction to the linear linewidth value.