  We demonstrate optical manipulation of the position of a domain wall in a
dilute magnetic semiconductor, GaMnAsP. Two main contributions are identified.
Firstly, 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. Secondly, 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 tweezer like ability to position and locally probe
domain walls.
