Time-resolved x-ray microscopy of spin-torque-induced magnetic vortex gyration.
Time-resolved x-ray microscopy is used to image the influence of alternating high-density currents on the magnetization dynamics of ferromagnetic vortices. Spin-torque-induced vortex gyration is observed in micrometer-sized permalloy squares. The phases of the gyration in structures with different chirality are compared to an analytical model and micromagnetic simulations, considering both alternating spin-polarized currents and the current's Oersted field. In our case the driving force due to spin-transfer torque is about 70% of the total excitation while the remainder originates from the current's Oersted field. This finding has implications to magnetic storage devices using spin-torque driven magnetization switching and domain-wall motion.
Institut für Angewandte Physik und Zentrum für Mikrostrukturforschung, Universität Hamburg, Jungiusstrasse 11, 20355 Hamburg, Germany. mbolte@physik.uni-hamburg.de
Markus
M
Bolte
Guido
G
Meier
Benjamin
B
Krüger
André
A
Drews
René
R
Eiselt
Lars
L
Bocklage
Stellan
S
Bohlens
Tolek
T
Tyliszczak
Arne
A
Vansteenkiste
Bartel
B
Van Waeyenberge
Kang Wei
KW
Chou
Aleksandar
A
Puzic
Hermann
H
Stoll