Manipulating exchange bias using all-optical helicity-dependent switching

Deterministic all-optical control of magnetization without an applied magnetic field has been reported for various materials such as ferrimagnetic and ferromagnetic thin films, as well as granular recordingmedia. Herewe demonstrate optical control of the magnetic configuration of an antiferromagnetic layer through the exchange bias interaction using the helicity of a femtosecond pulsed laser on IrMn/[Co/Pt] xN antiferromagnetic/ferromagnetic heterostructures. We show that the magnitude and the sign of the exchange bias field can be deterministically controlled without any applied magnetic field, only by changing the helicity of the light, the laser fluence, or the number of light pulses. We also present the combined effects of laser pulses with an applied magnetic field. This study lays the foundation for the development of newapplications based on spintronic devices where the exchange bias phenomenon is routinely used to pin the magnetization orientation of a magnetic layer in one direction.