Geometrical confinement of a domain wall in a nanocontact between two NiFe wires

Abstract

A nanocontact structure (typically 22×34 nm2) between two NiFe wires was fabricated by an electron-beam lithography and a lift-off method, and the magnetoresistance was measured. The magnetization switching process was artificially controlled by engineering the sample geometry to realize a magnetic structure with a single domain wall (DW) trapped in the nanocontact area. This domain structure was confirmed by magnetic force microscopy observations. The magnetization rotation of 180° was realized within the nanocontact area. The contribution of the DW to the resistance was negative, which can be understood on the basis of anisotropic magnetoresistance.

Reversal processes and domain wall pinning in polycrystalline Co-nanowires

“…8͑b͒ would naively lead to the interpretation that the DWR is negative. However, as has already been pointed out by other authors, 21,22 for a system with in-plane magnetization one has to take into account that contributions from the AMR play an important role. We thus checked the domain configuration by Monte Carlo simulations.…”

“…Due to the strong dependence of the coercive field on the wire width, such a system is commonly used to pin a domain wall in the center region between both wire parts. 21 Figure 8͑a͒ shows the longitudinal MR of a Pt-capped cobalt wire with a thickness of 30 nm cobalt and two different wire widths, 85 nm and 700 nm, respectively. Figure 8͑b͒ shows the MR behavior of the same wire, however, the voltage leads were placed in a distance of only 500 nm from the center region where the wider and the narrower part of the nanowire merge.…”

Magnetotransport through Nanoconstriction in Ferromagnetic Semiconductor (Ga,Mn)As

“…Thi s clearl y shows a negati ve contri buti on of D W to the resisti vi ty . Thi s i s, however, not very surpri sing since several autho rs ha ve al so i denti Ùed a negati ve contri buti on of do m ain wal l s to the resisti vi ty i n m etal li c ferro m agneti c m icro wi res [9].…”

Dependence of Domain-Wall Depinning Threshold Current on Pinning Profile

“…Increasing the magnitude of the magnetic field further, the resistance gradually decreases until a sharp rise in resistance is observed at around 15 Oe. The gradual decrease in resistance may be understood as the additional AMR contribution due to the displacement of the DW from the center of the constriction [23], while the sharp rise in resistance occurs due to DW depinning. The magnetization switching mechanism was also investigated using focused MOKE measurements, as shown in Fig.…”