Light switches magnets at ultrafast speeds

Sept. 1, 2007
All-optical switching of magnetic storage media has been widely believed to be impossible due to the insufficient angular momentum of photons.

All-optical switching of magnetic storage media has been widely believed to be impossible due to the insufficient angular momentum of photons. Now, researchers at Nijmegen University (Nijmegen, Netherlands) have demonstrated that magnetization can indeed be reversed experimentally by light at ultrafast speeds. The scientists used a single 40 fs circularly polarized laser pulse to permanently reverse magnetization in the ferromagnetic alloy gadolinium iron cobalt (Gd22Fe74.6Co3.4), a material useful for data storage.

This optically induced ultrafast magnetization reversal is the combined result of femtosecond-laser heating of the magnetic system to just below the Curie point of 500 K for GdFeCo, and the circularly polarized 800 nm laser light simultaneously acting as a magnetic field. The Ti:sapphire laser beam is scanned across the sample while the left- and right-circular polarization of the beam is simultaneously modulated. The final state of the magnetization is stable and can be unambiguously determined by the helicity of the laser pulse. The group estimates that the technique enables subpicosecond switching speeds, a result that could improve storage capability in devices such as hard-disk drives, magneto-resistive random access memory, and magneto-optical disks. Contact Claudiu Stanciu at [email protected].

Sponsored Recommendations

Request a quote: Micro 3D Printed Part or microArch micro-precision 3D printers

April 11, 2024
See the results for yourself! We'll print a benchmark part so that you can assess our quality. Just send us your file and we'll get to work.

Request a free Micro 3D Printed sample part

April 11, 2024
The best way to understand the part quality we can achieve is by seeing it first-hand. Request a free 3D printed high-precision sample part.

How to Tune Servo Systems: The Basics

April 10, 2024
Learn how to tune a servo system using frequency-based tools to meet system specifications by watching our webinar!

Precision Motion Control for Sample Manipulation in Ultra-High Resolution Tomography

April 10, 2024
Learn the critical items that designers and engineers must consider when attempting to achieve reliable ultra-high resolution tomography results here!

Voice your opinion!

To join the conversation, and become an exclusive member of Laser Focus World, create an account today!