Ferromagnetic domain wall manipulation using optically induced thermal gradients

Magnetic domain walls can be manipulated by thermal gradients. A local thermal gradient can be generated by illuminating the surface of a thin film sample with a focused femtosecond laser beam in relation to its intensity profile. We investigate the magnetic domain structures of a ferromagnetic [Co/Pt](3) multilayers under laser illumination. We create thermal gradients by either a stationary or a moving pulsed laser beam. Following the laser illumination, we use x-ray circular magnetic dichroism as a magnetic contrast mechanism in photoemission electron microscopy in order to image the magnetic domains. Our experimental results show that the domain walls drift towards the regions of higher temperature and align themselves parallel to the laser beam motion, leading to domains elongated in that direction.