Ultrashort XUV and soft x-ray to probe femtomagnetism effect, par Emmanuelle Jal - ISMO

Ultrashort XUV and soft x-ray to probe femtomagnetism effect

Emmanuelle Jal (24 nov 11h)

Laboratoire de Chimie Physique Matière Rayonnement, Sorbonne Université

Who has never played with magnet ? Additionally to its fascinating invisible attraction, magnet are nowadays widely used in our daily life since compact electronic devices often contain numerous functional magnetic components. Indeed the easiness of magnetization manipulation make it an ideal tool for logic and memory devices. Applying an external magnetic field or electronic current are currently the principal way of manipulating the magnetization of ultra-thin films. However one can also use optical pulses to change the magnetic state. This optical excitation of magnetic material imply a sub-picosecond dynamics that has been discovered in 1996 by Eric Beaurepaire and Jean-Yves Bigot and has opened the new field of femtomagnetism in condensed matter physics. Even after two decades of studies and debates, the mechanisms of ultrafast demagnetization remain disputed. In order to bring new experimental informations into this field, and with the advent of femtosecond X-rays sources, I am performing time resolved soft X-rays based pump/probe techniques on ultrathin ferromagnetic thin films. For this seminar, I will give an overview of what can be done with XUV and soft x-ray short pulses to probe electronic, magnetic and structural dynamic.

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