Spin-transfer-torque excitations in ferromagnetic nanostructures: spin torque oscillators

CIC nanoGUNE Seminars

Speaker: Ferran Macia, Universitat Barcelona, Barcelona, Spain
When: 2014/09/22
13:00
Place: nanoGUNE seminar room, Tolosa Hiribidea 76, Donostia - San Sebastian
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Spin-transfer-torque excitations in ferromagnetic nanostructures: spin torque oscillators

**Host** : L.Hueso Controlling the dynamics of magnetization in ferromagnetic (FM) thin films is essential to a new generation of wave-computing and on-chip communication devices working at high frequency and low power. Nanometer scale electrical contacts to ferromagnetic thin films (STNOs) can carry sufficient current densities to excite magnetization dynamics through the spin-transfer-torque effect resulting in either localized or propagating short wavelength spin waves. In this talk I will overview the spin-transfer-torque magnetic excitations in ferromagnetic thin films and focus on the spin waves and the dynamics created by STNOs. I will review some applications of spin-wave patterns created from STNOs and their interactions with background oscillations. I will show you some recent results on imaging localized excitations ~100nm with XMCD microscopy. We will also discuss recent advances in the study of magnetic droplet solitons (excitations of reversed spins that are strongly localized precess in-phase). In this presentation I will show that magnetic droplet solitons can be stabilized in a spin transfer nanocontact, exhibiting a strong hysteretic response to fields and currents and a nearly fully reversed magnetization. These observations, in addition to their fundamental interest, open up new applications for magnetic droplet solitons as multi-state high frequency current and field tunable oscillators. [1] F. MaciÃ et al. Nanotechnology 22 095301 (2011) [2] F. MaciÃ et al. Nanotechnology 25 045303 (2014) [3] S. M. Mohseni et al., Science 339, 1295 (2013) [4] F. MaciÃ et al. arXiv:1408.1902 (2014)