Abstract
Using transport measurements and micromagnetic simulations we have investigated the domain wall motion driven by spin-transfer torques in all-perpendicular hexagonal nanopillar spin-valves. In particular, we probe domain walls nucleated in the free layer of the spin-valves, which are then pinned in the devices. We have determined both the field-current state diagrams for the domain-wall state and the thermally activated dynamics of the nucleation and depinning processes. We show that the nucleation process is well-described by a modified Néel-Brown model taking into account the spin-transfer torque, whereas the depinning process is independent of the current. This is confirmed by an analytical calculation which shows that spin-torques have no effect on the Arrhenius escape rate associated with thermally activated domain wall depinning in this geometry. Furthermore, micromagnetic simulations indicate that spin-transfer only weakly affects the domain wall motion, but instead modifies the inner domain wall structure.
Original language | English (US) |
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Article number | 214429 |
Journal | Physical Review B - Condensed Matter and Materials Physics |
Volume | 86 |
Issue number | 21 |
DOIs | |
State | Published - Dec 28 2012 |
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics