Probing the spin polarization of current by soft x-ray imaging of current-induced magnetic vortex dynamics.
Time-resolved soft x-ray transmission microscopy is applied to image the current-induced resonant dynamics of the magnetic vortex core realized in a micron sized Permalloy disk. The high spatial resolution better than 25 nm enables us to observe the resonant motion of the vortex core. The result also provides the spin polarization of the current to be 0.67+/-0.16 for Permalloy by fitting the experimental results with an analytical model in the framework of the spin-transfer torque.
Kasai
Shinya
S
Institute for Chemical Research, Kyoto University, Uji 611-0011, Japan.
Fischer
Peter
P
Im
Mi-Young
MY
Yamada
Keisuke
K
Nakatani
Yoshinobu
Y
Kobayashi
Kensuke
K
Kohno
Hiroshi
H
Ono
Teruo
T