6.3 Ratchet Effect in Magnetic Domain Wall Motion
153
Operation
When an electric current is passed through each Cu wire, local magnetic
fields, H L , H M or H R are generated. These local magnetic fields act on the left
end, the main part of the wire with notches and on the right end of the magnetic wire,
respectively. As is evident from Fig. 6.8, H L and H R can trigger the nucleation of a
domain wall at the left and right end of the magnetic wire, respectively. Hence, the
direction of propagation of a domain wall can be precisely controlled by the local
fields, H L and H R .
Figure 6.9i exhibits typical variation of resistance with the application of an
external magnetic field (H ext ) of the trilayered magnetic wire with asymmetric
Fig. 6.9 Variation of resistance as a function of magnetic field in a trilayered NiFe (5 nm)/Cu
(20 nm)/NiFe (20 nm) spin valve magnetic nanowire structure with asymmetric notches. i Magnetoresistance curve of the spin valve system, ii magnetoresistance curve when a magnetic domain
wall is injected into the NiFe (20 nm) layer from the left end of the magnetic wire by the pulsed H L ,
iii magnetoresistance curve when a magnetic domain wall is injected into the NiFe (20 nm) layer
from the right end of the magnetic wire by pulsed H R (Himeno et al. 2005)
153
Operation
When an electric current is passed through each Cu wire, local magnetic
fields, H L , H M or H R are generated. These local magnetic fields act on the left
end, the main part of the wire with notches and on the right end of the magnetic wire,
respectively. As is evident from Fig. 6.8, H L and H R can trigger the nucleation of a
domain wall at the left and right end of the magnetic wire, respectively. Hence, the
direction of propagation of a domain wall can be precisely controlled by the local
fields, H L and H R .
Figure 6.9i exhibits typical variation of resistance with the application of an
external magnetic field (H ext ) of the trilayered magnetic wire with asymmetric
Fig. 6.9 Variation of resistance as a function of magnetic field in a trilayered NiFe (5 nm)/Cu
(20 nm)/NiFe (20 nm) spin valve magnetic nanowire structure with asymmetric notches. i Magnetoresistance curve of the spin valve system, ii magnetoresistance curve when a magnetic domain
wall is injected into the NiFe (20 nm) layer from the left end of the magnetic wire by the pulsed H L ,
iii magnetoresistance curve when a magnetic domain wall is injected into the NiFe (20 nm) layer
from the right end of the magnetic wire by pulsed H R (Himeno et al. 2005)