Femtomagnetism in Nature Photonics
An increase of the exchange energy can be induced by applying an ultrashort light pulse. A new route to high speed data storage?
 
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(Photo)Exciting movie: biomolecules on stage

 It took us eight years, and it only features a few picoseconds of a protein life in reaction to an energy shot. But this atom-scale Truman show, proposed in the ERC Femtoscopy project, has now -literally- seen the light. Using Femtosecond Stimulated Raman Scattering, we determined the whole spectrum of vibrational amplitudes of a photo-excited heme protein with extremely high temporal resolution, which allows animating the molecular normal modes. Enjoy the full story, providing new insights for the energy trasport at the atomic scale, in the Nature Chemistry paper

Last Updated ( Tuesday, 04 October 2016 )
 
Between the spins

 The exchange interaction induces spins alignement in magnetic materials, and is responsible for ferromagnetism and antiferromagnetism. Our understanding of exchange mechanism goes back the work of Heisenberg in 1926, which revealed that it arises from the combination of the Coulomb interaction and the Pauli exclusion principle. By implementing Femtosecond Stimulated Two-magnon Raman Scattering we photoinduce and detect an increase ot the exchange energy over a few tens of femtoseconds. Our results, just appeared in Nature Photonics ,  may have implications for magnetic recording:

Last Updated ( Thursday, 30 July 2015 )
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How slow does a glass flow?

 Does the glass cease to flow at some finite temperature?” Answering this question––of pivotal importance for glass formation theories––would require ridiculously long observation times. We circumvent this infeasibility relating the (directly inaccessible) ultraviscous flow of a liquid to the elastic properties of the corresponding glass, which we measure as a function of its age. The older the glass, the lower the temperature at which viscosity can be determined. Taking advantage of physical vapor deposition, we rapidly obtain a wide spectrum of ages rivaling those of millenary ambers, enabling viscosity determinations at values as large as those pertaining to the asthenosphere. Our result, recently appeared in PNAS , ultimately rules out the finite-temperature divergence of the molecular diffusion timescale in a glass.

Read the full story on PNAS paper

Last Updated ( Friday, 31 July 2015 )
 

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