Effects of Magnetic Domain Walls on the Anisotropic Magnetoresistance in NiFe Nanowires.

We show that a type of magnetic domain walls (DWs) can be monitored by anisotropic magnetoresistance (AMR) measurements due to a specific DW volume depending on the DW type in NiFe magnetic wires. A circular DW injection pad is used to generate DWs at a low magnetic field, resulting in reliable DW introduction into magnetic wires. DW pinning is induced by a change of DW energy at an asymmetric single notch.

Distortion of Magnetic Domain Wall Measured by Magneto-Resistance Changes in a Co Nanoring.

The electrical anisotropic magneto-resistance (AMR) measurements were performed to see the formation of a 360 degree magnetic domain wall (360 DW) and distortion of the magnetic moments in a Co nanoring structure. Since the 360 DW is consisted of two 180 degree DWs, a decrease of the resistance was found in the switching process from the vortex to reverse onion state by the AMR effects, which is consistent with micromagnetic simulations. In addition, a decrease of the resistance in the switching process from the onion to vortex state was observed by the distortion of the local magnetic moments due to an applied magnetic field.

Asymmetric angular dependence of domain wall motion in magnetic nanowires.

An angular dependence of domain wall (DW) motion is studied in a magnetic wire consisting of a giant-magnetoresistance spin-valve. A DW pinning site is formed by a single notch, where a conventional linear one and a specially designed tilted one are compared. The asymmetric angular dependence was found in the DW depinning behavior with the tilted notch.

Fabrication of isolated CoGdTb magnetic nanodots with perpendicular magnetic anisotropy.

The authors report that a closely-packed hybrid nanostructure can be fabricated by using simple sputtering deposition and anodized aluminum oxide (AAO) templates. In order to isolate CoGdTb magnetic materials with the AAO template, carbon nanotubes (CNTs) were incorporated into the AAO template. Scanning electron microscopy reveals that the nanodots are formed exactly on the top of CNTs, which are placed in a regular arrangement over a wide range area.

Current-induced domain wall nucleation and its pinning characteristics at a notch in a spin-valve nanowire.

The characteristics of domain wall (DW) pinning at a notch in a spin-valve nanowire were investigated when a DW was created by a current, flowing into a spin-valve nanowire. It was found that DW pinning at a notch is quite sensitive to the magnitude of the current and its polarity. The current-polarity dependence of DW pinning is likely due to the spin structure in the core of the DW, which is determined by an Oersted field from the current in a Cu layer.

Magnetic dipolar interaction in NiFe nanodot arrays formed on vertical carbon nanotubes.

A new and simple method for the fabrication of densely packed magnetic nanodot arrays was developed using conventional sputtering deposition at room temperature. An anodized alumina template was employed for the formation of nanodot assemblies, consisting of carbon nanotubes (CNTs) and magnetic nanodot arrays. Each nanodot was formed exactly on top of a CNT and was arranged with a well-ordered structure in a wide range of area.

Characteristics of domain wall pinning and depinning in a three-terminal magnetic Y-junction.

The characteristics of domain wall (DW) pinning and propagation in a three-terminal magnetic Y-junction were investigated, where the junction consisted of two input and one output wires. The output switching depends strongly on the junction angle (α). Junctions with high angles of α>9.

Insertion of a specular reflective and transmissive nano-oxide layer into giant magnetoresistance spin-valve structure.

We have studied the influence of the insertion of a nano-oxide layer (NOL) into a magnetic GMR spin-valve. It was found that the spin-valve with NOL has a higher GMR ratio than that of the normal spin-valve without NOL. Naturally formed NOL without vacuum break shows a uniform layer, which effectively suppresses the current shunt, resulting in the reduction of the sheet resistance of GMR.