Mechanism of helicity-dependent all-optical switching in ferromagnets
In plain words
A single laser pulse can flip the magnetization of some alloys with two opposed magnetic sublattices, and repeated circularly polarized pulses can flip ordinary ferromagnetic films. The first case is understood as fast heating of the two coupled sublattices; what drives switching that depends on the light's handedness is not settled.
Precise statement
Helicity-independent single-pulse switching in ferrimagnetic GdFeCo is explained by different demagnetization times of the Gd and Fe sublattices with exchange-mediated angular momentum transfer (Ostler et al. 2012). For helicity-dependent multi-pulse switching in Co/Pt multilayers and FePt granular media (Lambert et al. 2014), determine the relative roles of the inverse Faraday effect, magnetic circular dichroism (helicity-dependent absorption) and thermally assisted domain-wall motion, and whether single-pulse switching is possible in a pure ferromagnet. An answer is the mechanism with quantitative switching probability versus fluence and helicity.
What would settle it
Pulse-resolved switching statistics versus helicity, fluence and wavelength compared with atomistic spin simulations including both the inverse Faraday field and dichroic heating.
Status in the literature
The helicity-independent case in GdFeCo is accepted as thermal; the helicity-dependent case in ferromagnets remains debated.
Results
No results have been posted on this problem yet.
Post a result · how results are checked
Sign in to follow or save this problem
Comments (0)
Comments are not records: they are not signed, stamped or logged. How comments work
No comments yet.
Sign in to comment.