TY - JOUR
T1 - Current-induced magnetic domain wall motion below intrinsic threshold triggered by Walker breakdown
AU - Koyama, T.
AU - Ueda, K.
AU - Kim, K. J.
AU - Yoshimura, Y.
AU - Chiba, D.
AU - Yamada, K.
AU - Jamet, J. P.
AU - Mougin, A.
AU - Thiaville, A.
AU - Mizukami, S.
AU - Fukami, S.
AU - Ishiwata, N.
AU - Nakatani, Y.
AU - Kohno, H.
AU - Kobayashi, K.
AU - Ono, T.
N1 - Funding Information:
This work was partly supported by a Grant-in-Aid for Scientific Research (S) and ‘Funding program for world-leading innovative R&D on science and technology’ (FIRST program) from the Japan Society for the Promotion of Science and the Collaborative Research Program of Institute for Chemical Research, Kyoto University.
PY - 2012/8/26
Y1 - 2012/8/26
N2 - Controlling the position of a magnetic domain wall with electric current may allow for new types of non-volatile memory and logic devices. To be practical, however, the threshold current density necessary for domain wall motion must be reduced below present values. Intrinsic pinning due to magnetic anisotropy, as recently observed in perpendicularly magnetized Co/Ni nanowires, has been shown to give rise to an intrinsic current threshold J th 0. Here, we show that domain wall motion can be induced at current densities 40% below J th 0 when an external magnetic field of the order of the domain wall pinning field is applied. We observe that the velocity of the domain wall motion is the vector sum of current- and field-induced velocities, and that the domain wall can be driven against the direction of a magnetic field as large as 2,000Â Oe, even at currents below J th 0. We show that this counterintuitive phenomenon is triggered by Walker breakdown, and that the additive velocities provide a unique way of simultaneously determining the spin polarization of current and the Gilbert damping constant.
AB - Controlling the position of a magnetic domain wall with electric current may allow for new types of non-volatile memory and logic devices. To be practical, however, the threshold current density necessary for domain wall motion must be reduced below present values. Intrinsic pinning due to magnetic anisotropy, as recently observed in perpendicularly magnetized Co/Ni nanowires, has been shown to give rise to an intrinsic current threshold J th 0. Here, we show that domain wall motion can be induced at current densities 40% below J th 0 when an external magnetic field of the order of the domain wall pinning field is applied. We observe that the velocity of the domain wall motion is the vector sum of current- and field-induced velocities, and that the domain wall can be driven against the direction of a magnetic field as large as 2,000Â Oe, even at currents below J th 0. We show that this counterintuitive phenomenon is triggered by Walker breakdown, and that the additive velocities provide a unique way of simultaneously determining the spin polarization of current and the Gilbert damping constant.
UR - http://www.scopus.com/inward/record.url?scp=84871068906&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84871068906&partnerID=8YFLogxK
U2 - 10.1038/nnano.2012.151
DO - 10.1038/nnano.2012.151
M3 - Article
C2 - 22961306
AN - SCOPUS:84871068906
VL - 7
SP - 635
EP - 639
JO - Nature Nanotechnology
JF - Nature Nanotechnology
SN - 1748-3387
IS - 10
ER -