Deterministic generation of single domain wall in ferromagnetic nanowire using local Oersted field

Domain walls (DWs) in magnetic nanowire have been recognised to have the potential to be used in ultra-high density storage and non-volatile logic devices. For actual applications, the creation of DW on the nanosecond timescale and perfect control of its dynamics is critical. The existing method for creating DW in which local Oersted field is used, two DWs are always nucleated; a head-to-head (HH) and a tail-to-tail (TT) DWs. Due to the intrinsic characteristics of these DWs, they either annihilate or form a coupled DW(1-3). This leads to the stochastic behaviour of DW generation(1). It has been previously reported that the minimum separation of two DWs for their stable existence is approximately 2.6μm(4). Therefore, for strip line width less than 2.6μm there is a very high probability for mutual annihilation of the two generated DWs if no external magnetic field is applied to drive them apart.