A magnetic shift register uses the inherent, natural properties of domain walls
in magnetic materials to store data. The shift register uses spin electronics without
changing the physical nature of its constituent materials. The shift register comprises
a fine track or strip of magnetic materials. Information is stored as domain walls
in the track. An electric current is applied to the track to move the magnetic
moments along the track past a reading or writing device. In a magnetic material
with domain walls, a current passed across the domain wall moves the domain wall
in the direction of the current flow. As the current passes through a domain, it
becomes "spin polarized". When this spin polarized current passes through the next
domain and across a domain wall, it develops a circle of spin torque. This spin
torque moves the domain wall.