The Ultrafast Einstein-De Haas Effect

Abstract

The original observation of the Einstein-de Haas effect was a landmark experiment in the early history of modern physics that illustrates the relationship between magnetism and angular momentum. Today the effect is still discussed in elementary physics courses to demonstrate that the angular momentum associated with the aligned electron spins in a ferromagnet can be converted to mechanical angular momentum by reversing the direction of magnetisation using an external magnetic field. In recent times, a related problem in magnetism concerns the time-scale over which this angular momentum transfer can occur. It is known experimentally for several metallic ferromagnets that intense photoexcitation leads to a drop in the magnetisation on a time scale shorter than 100 fs, a phenomenon called ultrafast demagnetisation. The microscopic mechanism for this process has been hotly debated, with one key question still unanswered: where does the angular momentum go on these sub-picosecond time scales? Here we show using femtosecond time-resolved x-ray diffraction that a large fraction of the angular momentum lost from the spin system on the laserinduced demagnetisation of ferromagnetic iron is transferred to the lattice on sub-picosecond timescales, manifesting as a transverse strain wave that propagates from the surface into the bulk. By fitting a simple model of the x-ray data to simulations and optical data, we roughly estimate that the angular momentum occurs on a time scale of 200 fs and corresponds to 80% of the angular momentum lost from the spin system. Our results show that interaction with the lattice plays an essential role in the process of ultrafast demagnetisation in this system.

39 pages, 2 tables, 7 figures

References in corpus (10)

• Super-Diffusive Spin-Transport as a Mechanism of Ultrafast Demagnetization
• All-optical control of ferromagnetic thin films and nanostructures
• Ultrafast transport of laser-excited spin polarized carriers in Au/Fe/MgO(001)
• Many-body theory of ultrafast demagnetization and angular momentum transfer in ferromagnetic transition metals
• Role of Spin Flips versus Spin Transport in Non Thermal Electrons Excited by Ultrashort Optical Pulses in Transition Metals
• Accumulative magnetic switching of ultra-high-density recording media by circularly polarized light
• Femtosecond x-ray absorption spectroscopy of spin and orbital angular momentum in photoexcited Ni films during ultrafast demagnetization
• Dynamics of Einstein - de Haas Effect: Application to Magnetic Cantilever
• Quantum many-body dynamics of the Einstein-de Haas effect
• Magnetic switching in granular FePt layers promoted by near-field laser enhancement

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