Optical spin-transfer-torque-driven domain-wall motion in a ferromagnetic semiconductor.
We demonstrate optical manipulation of the position of a domain wall in a dilute magnetic semiconductor, GaMnAsP. Two main contributions are identified. First, photocarrier spin exerts a spin-transfer torque on the magnetization via the exchange interaction. The direction of the domain-wall motion can be controlled using the helicity of the laser. Second, the domain wall is attracted to the hot spot generated by the focused laser. Unlike magnetic-field-driven domain-wall depinning, these mechanisms directly drive domain-wall motion, providing an optical tweezerlike ability to position and locally probe domain walls.
Hitachi Cambridge Laboratory, Hitachi Europe Limited, Cambridge CB3 0HE, United Kingdom.
A J
AJ
Ramsay
Hitachi Cambridge Laboratory, Hitachi Europe Limited, Cambridge CB3 0HE, United Kingdom.
P E
PE
Roy
Hitachi Cambridge Laboratory, Hitachi Europe Limited, Cambridge CB3 0HE, United Kingdom.
J A
JA
Haigh
Hitachi Cambridge Laboratory, Hitachi Europe Limited, Cambridge CB3 0HE, United Kingdom.
R M
RM
Otxoa
The Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, United Kingdom.
A C
AC
Irvine
Faculty of Mathematics and Physics, Charles University in Prague, Ke Karlovu 3, 121 16 Prague 2, Czech Republic.
T
T
Janda
School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, United Kingdom.
R P
RP
Campion
School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, United Kingdom.
B L
BL
Gallagher
Hitachi Cambridge Laboratory, Hitachi Europe Limited, Cambridge CB3 0HE, United Kingdom and Institute of Physics ASCR, Cukrovarnická 10, 162 53 Praha 6, Czech Republic.
J
J
Wunderlich