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S. Goolaup et al.
quiescent power, high scalability and high speed. The manipulation of the magnetization direction of nanomagnets, via magnetic field [3–8] or spin transfer torque
effect [9], has spawned numerous techniques for magnetic logic [3–12]. In these
logic schemes, different physical designs are needed for full logic functionalities.
However, a logic which can be reconfigurable at run-time shall simplify the device
architecture by eliminating interconnects and can potentially increase the computing
speed. The reconfigurability makes the device attractive as a single device can then
be programmed for many applications [13]. Though conceptual proposals [14, 15] of
programmable spin logic exist, experimental demonstration of an all-magnetic reconfigurable logic is still lacking. Semiconductor based reconfigurable logic schemes
have been demonstrated combining the magnetism and semiconductor technologies
[16]. The logic operations in the device are performed by controlling the motion of
charge carriers in p-n junction diodes by the application of a magnetic field. Simple
circuit combinations of diode structures are used to perform various logic operations.
The propagation of magnetic domain wall (DW) in magnetic nanowires has been
proposed towards making high-density magnetic memories [17], spin logic devices
[3, 7] and shift registers [18, 19]. The approach to domain wall magnetic logic has
been to drive DW to switch the binary state of nanostructures. The success of these
technologies will rely inevitably on the perfect control and understanding of magnetic
DWs in nanowires. This has proven to be a challenging task, and much research has
been devoted to understanding the DW dynamics in magnetic nanowires [20–25].
Changes in the DW structure are significant in device applications where DW motion
is controlled via interaction with artificial defects, as the detailed spin distribution in
the wall affects the nature and strength of the pinning potential [25–27].
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. The fidelity of the data transmission may also depend on
preserving the DW structure. Although much progress has been made, to date there
has been a limited number of DW-based devices for industrial applications. In situ
control of the DW topological defects in nanowire conduits may pave the way for
novel DW logic applications [28].
2 Domain Wall Reconfigurable Logic
A DW based reconfigurable logic is proposed and demonstrated where-in controlled
motion of a domain wall in a magnetic network structure results in binary logical
operations [29]. The device is capable of performing all basic logic functionalities
on a single structure. The selection of a particular logic functionality is achieved
by using an in situ local Oersted field via a magnetic gate. The details of selective
motion of domain wall in network structures and the concept of magnetic charge
associated with DW are further elaborated in the chapter.
S. Goolaup et al.
quiescent power, high scalability and high speed. The manipulation of the magnetization direction of nanomagnets, via magnetic field [3–8] or spin transfer torque
effect [9], has spawned numerous techniques for magnetic logic [3–12]. In these
logic schemes, different physical designs are needed for full logic functionalities.
However, a logic which can be reconfigurable at run-time shall simplify the device
architecture by eliminating interconnects and can potentially increase the computing
speed. The reconfigurability makes the device attractive as a single device can then
be programmed for many applications [13]. Though conceptual proposals [14, 15] of
programmable spin logic exist, experimental demonstration of an all-magnetic reconfigurable logic is still lacking. Semiconductor based reconfigurable logic schemes
have been demonstrated combining the magnetism and semiconductor technologies
[16]. The logic operations in the device are performed by controlling the motion of
charge carriers in p-n junction diodes by the application of a magnetic field. Simple
circuit combinations of diode structures are used to perform various logic operations.
The propagation of magnetic domain wall (DW) in magnetic nanowires has been
proposed towards making high-density magnetic memories [17], spin logic devices
[3, 7] and shift registers [18, 19]. The approach to domain wall magnetic logic has
been to drive DW to switch the binary state of nanostructures. The success of these
technologies will rely inevitably on the perfect control and understanding of magnetic
DWs in nanowires. This has proven to be a challenging task, and much research has
been devoted to understanding the DW dynamics in magnetic nanowires [20–25].
Changes in the DW structure are significant in device applications where DW motion
is controlled via interaction with artificial defects, as the detailed spin distribution in
the wall affects the nature and strength of the pinning potential [25–27].
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. The fidelity of the data transmission may also depend on
preserving the DW structure. Although much progress has been made, to date there
has been a limited number of DW-based devices for industrial applications. In situ
control of the DW topological defects in nanowire conduits may pave the way for
novel DW logic applications [28].
2 Domain Wall Reconfigurable Logic
A DW based reconfigurable logic is proposed and demonstrated where-in controlled
motion of a domain wall in a magnetic network structure results in binary logical
operations [29]. The device is capable of performing all basic logic functionalities
on a single structure. The selection of a particular logic functionality is achieved
by using an in situ local Oersted field via a magnetic gate. The details of selective
motion of domain wall in network structures and the concept of magnetic charge
associated with DW are further elaborated in the chapter.