Current induced localized domain wall oscillators in NiFe/Cu/NiFe submicron wires

We experimentally demonstrate domain wall (DW) oscillators excited by in-plane ac current through permalloy based pseudo-spin valve wires, which contain one pair of artificial protrusions. By measuring the spin-transfer-torque induced resonance of a pinned antiparallel transverse DW, under transverse external fields, we show that the antiparallel transverse DW oscillates with a resonance frequency as high as 2.92 GHz, depending on the widths of protrusions. For DW oscillations induced by injection of dc currents, the observed peaks in dV/dI associated with the reversible change of magnetoresistance are attributed to the reversible motions of the DW. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4770306]