Ferromagnetic Domain Wall Manipulation Using Optically Induced Thermal Gradients

Abstract

Magnetic domain walls can be manipulated by the 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 multilayer 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 photoelectron emission microscopy in order to image the magnetic domains. Our experimental results show that the domain walls can drift towards the regions with higher temperature, and align themselves parallel to the laser beam motion, leading to domains elongated in that direction.

Keywords: X-ray Magnetic Circular Dichroism, Photoemission Electron Microscopy, Magnetic Domains, All-Optical Switching