Laser-Assisted Magnetization Reversal Dynamics for Magneto-Optical Storage Devices

Sun Yat-Sen University researchers have demonstrated a new technique of recording on ferromagnetic films with a laser-assisted ultrafast magnetization reversal dynamics.

The team of Tianshu Lai showed the laser-assisted magnetic recording under a saturated external magnetic field on a time scale of sub-picoseconds.

The recording method makes use of a combination of a time-resolved polar Kerr spectroscopy and an alternating magnetic field. This magnetic field re-initializes the gadolinium-iron-cobalt (GdFeCo) thin films’ magnetization state. The magnetization reversal can take place in a time scale of sub-nanoseconds. This enables future magneto-optical storage devices to deliver ultrafast data writing at a maximum of 1-gigahertz speed, and high recording densities. This high speed is no less than 30 times faster as compared to the current hard disks used in computers.

Tianshu Lai stated that the magnetization reversal rate is proportional to the external magnetic field. Lai continued that the real thermo-magnetic recording must occur between the picosecond ranges when a magnetic field smaller than the recording films’ coercivity is applied.