LAUSR

The dynamic behaviors of a DW pinned by a notch pair or a single notch with different notch depth are studied. It is found that, in a relatively large current density range, the oscillation frequency of the DW becomes frozen and independent on current density when pinned by a notch pair with the notch depth larger than 12 nm. The current density range for frequency freeze can be tuned by the notch depth. A chain of notch pairs is design to introduce more pinned DW into the nanowire. By increasing the number of the DWs and applying a proper magnetic field, the oscillation amplitude can be greatly enhanced. Our finding suggests nanowires with a series of deep notch pairs may have an important application for the development of domain wall based spin-transfer nano-oscillators (DWSTOs) with a high tolerance for current fluctuation.