Direct observation of domain wall evolution at a bifurcation in magnetic network structures

Maddu

et al. 2015

Domain wall (DW) based logic and memory devices require precise control and manipulation of DW in nanowire conduits. The topological defects of Transverse DWs (TDW) are of paramount importance as regards to the deterministic pinning and movement of DW within complex networks of conduits. In-situ control of the DW topological defects in nanowire conduits may pave the way for novel DW logic applications. In this work, we present a geometrical modulation along a nanowire conduit, which allows for the topological rectification/inversion of TDW in nanowires. This is achieved by exploiting the controlled relaxation of the TDW within an angled rectangle. Direct evidence of the logical operation is obtained via magnetic force microscopy measurement.

Section: Resultssupporting

confidence: 65%

Transverse Domain Wall Profile for Spin Logic Applications

Maddu

et al. 2015

“…in symmetric structure, the DW experiences similar potential barriers along the UHR and LHR. The motion of the DW is determined by the arrangement of the topological edge defects making it chirality dependent 20 21 22 . However, when we introduce an offset at the bifurcation, the potential barriers experienced by the DW are different in both directions.…”

Section: Resultsmentioning

confidence: 99%

Reconfigurable logic via gate controlled domain wall trajectory in magnetic network structure

Sethi

et al. 2016

An all-magnetic logic scheme has the advantages of being non-volatile and energy efficient over the conventional transistor based logic devices. In this work, we present a reconfigurable magnetic logic device which is capable of performing all basic logic operations in a single device. The device exploits the deterministic trajectory of domain wall (DW) in ferromagnetic asymmetric branch structure for obtaining different output combinations. The programmability of the device is achieved by using a current-controlled magnetic gate, which generates a local Oersted field. The field generated at the magnetic gate influences the trajectory of the DW within the structure by exploiting its inherent transverse charge distribution. DW transformation from vortex to transverse configuration close to the output branch plays a pivotal role in governing the DW chirality and hence the output. By simply switching the current direction through the magnetic gate, two universal logic gate functionalities can be obtained in this device. Using magnetic force microscopy imaging and magnetoresistance measurements, all basic logic functionalities are demonstrated.

“…The circular pad is used for nucleating and injecting a DW into the longitudinal nanowire. A 6-μm-long and 100-nm-wide transverse nanowire is positioned at a distance of 1 μm from the output branch to assign chirality to the injected DW 12 18 . When the magnetization of the transverse nanowire is aligned along the + y direction, the injected DW attains an ACW chirality, conversely, a CW chirality DW is injected if the magnetization is aligned along the − y direction.…”

Section: Resultsmentioning

confidence: 99%

“…The selective switching was ascribed to the arrangement of topological edge charges of DW at the bifurcation of the network structure 11 . We previously reported selective trajectory of a transverse DW (TDW) in Y-shaped branch structure via a complex interaction of edge defects with the vertex at the bifurcation 12 . The above observations have direct application in the formation of 1D Dirac strings in an artificial spin ice lattice 2 11 .…”

mentioning

confidence: 99%

Direct observation of deterministic domain wall trajectory in magnetic network structures

Sethi

et al. 2016

Controlling the domain wall (DW) trajectory in magnetic network structures is crucial for spin-based device related applications. The understanding of DW dynamics in network structures is also important for study of fundamental properties like observation of magnetic monopoles at room temperature in artificial spin ice lattice. The trajectory of DW in magnetic network structures has been shown to be chirality dependent. However, the DW chirality periodically oscillates as it propagates a distance longer than its fidelity length due to Walker breakdown phenomenon. This leads to a stochastic behavior in the DW propagation through the network structure. In this study, we show that the DW trajectory can be deterministically controlled in the magnetic network structures irrespective of its chirality by introducing a potential barrier. The DW propagation in the network structure is governed by the geometrically induced potential barrier and pinning strength against the propagation. This technique can be extended for controlling the trajectory of magnetic charge carriers in an artificial spin ice lattice.