Ultrahigh differential mobility and velocity of Neel domain walls in spin valves with planar-transverse polarizers and perpendicularly injected small currents

摘要

Transverse domain wall (TDW) dynamics in long and narrow spin valves with perpendicular current injection is theoretically investigated. We demonstrate that stable traveling-wave motion of TDWs with finite velocity survives for strong enough planar-transverse polarizers. For typical ferromagnetic materials (for example, Co) and achievable spin polarization (P = 0.6), TDWs acquire a velocity of 10(3) m/s under a current density below 10(7) A/cm(2). This efficiency is comparable with that of perpendicular polarizers. More importantly, in this case the wall has ultrahigh "differential mobility" around the onset of stable wall excitations. Our results open possibilities for developing magnetic nanodevices based on TDW propagation with low energy consumption. Also, analytics for parallel and perpendicular polarizers perfectly explains existing simulation findings. Finally, further boosting of TDWs by external uniform transverse magnetic fields is investigated and turns out to be efficient.