Optical spin-transfer-torque-driven domain-wall motion in a ferromagnetic semiconductor
Ramsay, A.J. and Roy, P.E. and Haigh, J.A. and Otxoa, R.M. and Irvine, A.C. and Janda, T. and Campion, R.P. and Gallagher, B.L. and Wunderlich, J. (2015) Optical spin-transfer-torque-driven domain-wall motion in a ferromagnetic semiconductor. Physical Review Letters, 114 (6). 067202. ISSN 0031-9007
Official URL: http://dx.doi.org/10.1103/PhysRevLett.114.067202
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.
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