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Résumé |
Magnetostriction links the shape of a magnetic material to its magnetization direction. Kittel recognized early
on the interest of applying this strain dynamically to induce magnetic resonance [1]. His ideas have seen a
recent revival of interest when combined to a wide range of optical or electrical acoustic wave excitation
techniques. These waves are widely used in the fields of semiconductors physics, nanophotonics, and
quantum optomechanics. In the Gigahertz range, they become relevant to magnetism physics, as these are
typically the eigenfrequencies of the magnetization in most ferromagnets. I will describe the work we have
been doing on (Ga,Mn)As using sub-GHz surface acoustic waves (SAWs) to manipulate, control, and switch
magnetization - even in the absence of any applied magnetic field [2,3,4]. I will detail the experimental
technique we have developed that enables us a spatio-temporal detection of these ultrasound driven
magnetization dynamics. I will conclude by some perspectives on the use of magneto-acoustics in both
magnetic and acoustic devices.
[1] L. Thevenard et al., “Irreversible magnetization switching using surface acoustic waves,” Phys. Rev. B,
vol. 87, no. 14, p. 144402, Apr. 2013.
[2] L. Thevenard et al., “Precessional magnetization switching by a surface acoustic wave,” Phys. Rev. B,
vol. 93, no. 13, p. 134430, Apr. 2016.
[3] P. Kuszewski et al., “Resonant magneto-acoustic switching: influence of Rayleigh wave frequency and
wavevector,” J. Phys. Condens. Matter, vol. 30, no. 24, p. 244003, Jun. 2018.
[4] P. Kuszewski et al., “Optical probing of Rayleigh wave driven magneto-acoustic resonance,”
arXiv:1806.11410, Jun. 2018.
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