Researchers observe shortest magnetic eventis

For the first time ever, physicists have been able to change the magnetic moment of a material using a light wave within one femtosecond – the fastest magnetic event ever observed.

Luminous elements, from which red arrows penetrate to the outside and from left to right flows a large red arrow.

Recording of the fast switching of magnetic moments by ultrafast light pulses: The red arrows mark the ordered magnetic moment of a layer stack of nickel (ferromagnet) and platinum (metal) before an ultra-short laser pulse inverts the magnetization of the two layerst © J.K. Dewhurst

Electronic properties of materials can be directly influenced via light absorption in under a femtosecond (10 -15 seconds), which is regarded as the limit of the maximum achievable speed of electronic circuits. In contrast, the magnetic moment of matter has only been able to be influenced up to now by a light and magnetism-linked process and roundabout way by means of magnetic fields, which is why magnetic switching takes that much longer and at least several hundred femtoseconds. A consortium of researchers from the Max Planck Institutes for Quantum Optics and for Microstructure Physics, of the Max Born Institute, at the University of Greifswald and Graz University of Technology have only now been able to manipulate the magnetic properties of a ferromagnetic material on a time scale of electrical field oscillations of visible light – and thus in sync with the electrical properties – by means of laser pulses. This influence was able to be accelerated by a factor of 200 and was measured and represented using time-resolved attosecond spectroscopy. The researchers described their experiment in the journal Nature .

Switch to the TU Graz News article to read more about the initial step towards coherent magnetism.


Univ.-Prof. Martin SCHULTZE
TU Graz | Institute of Experimental Physics
Petersgasse 16, 8010 Graz, Österreich
Tel. +43 316 873 8142