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arXiv · 1711.01234

THz-driven demagnetization with Perpendicular Magnetic Anisotropy: Towards ultrafast ballistic switching

Debanjan Polley·Matteo Pancaldi·Matthias Hudl·Paolo Vavassori·Sergei Urazhdin·Stefano Bonetti
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Abstract

We study THz-driven spin dynamics in thin CoPt films with perpendicular magnetic anisotropy. Femtosecond magneto-optical Kerr effect measurements show that demagnetization amplitude of about $1\%$ can be achieved with a peak THz electric field of $300$~kV/cm, and a corresponding peak magnetic field of $0.1$~T. The effect is more than an order of magnitude larger than observed in samples with easy-plane anisotropy irradiated with the same field strength. We also utilize finite-element simulations to design a meta-material structure that can enhance the THz magnetic field by more than an order of magnitude, over an area of several tens of square micrometers. Magnetic fields exceeding $1$~Tesla, generated in such meta-materials with the available laser-based THz sources, are expected to produce full magnetization reversal via ultrafast ballistic precession driven by the THz radiation. Our results demonstrate the possibility of table-top ultrafast magnetization reversal induced by THz radiation.

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Debanjan Polley, Matteo Pancaldi, Matthias Hudl, Paolo Vavassori, Sergei Urazhdin, Stefano Bonetti. 2017-11-03. THz-driven demagnetization with Perpendicular Magnetic Anisotropy: Towards ultrafast ballistic switching. https://doi.org/10.1088/1361-6463%2Faaa863

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