MFM Observation of Twin Pinning Sites on NiFe Nanowires

A train of symmetric twin pinning sites of varying distances on Permalloy nanowires of different widths fabricated with electron beam lithography (EBL) have been investigated using magnetic force microscope (MFM) measurement. Nanowires with a width from 600 to 900 nm with twin pinning sites at a separation from 1.1 μm to 4.6 μm have been found to favor the formation of transverse domain walls under perpendicular, longitudinal, and 45° externally applied magnetic fields. The pinning sites were found to have potential for both head-to-head and tail-to-tail transverse domain wall (DW) pinning at the remanent status under perpendicular, 45° and longitudinal applied magnetic field, while the details of the head-to-head DW pinning area and the tail-to-tail DW structure are subject to the nanowire widths, pinning sites separations, as well as the externally applied magnetic field directions.