Is perpendicular magnetic anisotropy essential to all-optical ultrafast spin reversal in ferromagnets?
- Indiana State Univ., Terre Haute, IN (United States). Dept. of Physics
- Indiana State Univ., Terre Haute, IN (United States). Office of Information Technology
- Univ. of Missouri-St. Louis, St. Louis, MO (United States). Office of the Chancellor and Center for Nanoscience, Depts. of Chemistry & Biochemistry and Physics & Astronomy
All-optical spin reversal presents a new opportunity for spin manipulations, free of a magnetic field. Most of all-optical-spin-reversal ferromagnets are found to have a perpendicular magnetic anisotropy (PMA), but it has been unknown whether PMA is necessary for spin reversal. Here we theoretically investigate magnetic thin films with either PMA or in-plane magnetic anisotropy (IMA). Our results show that spin reversal in IMA systems is possible, but only with a longer laser pulse and within a narrow laser parameter region. Spin reversal does not show a strong helicity dependence where the left- and right-circularly polarized light lead to the identical results. By contrast, the spin reversal in PMA systems is robust, provided both the spin angular momentum and laser field are strong enough while the magnetic anisotropy itself is not too strong. This explains why experimentally the majority of all-optical spin-reversal samples are found to have strong PMA and why spins in Fe nanoparticles only cant out of plane. It is the laser-induced spin–orbit torque that plays a key role in the spin reversal. Surprisingly, the same spin–orbit torque results in laser-induced spin rectification in spin-mixed configuration, a prediction that can be tested experimentally. Our results clearly point out that PMA is essential to spin reversal, though there is an opportunity for in-plane spin reversal.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). National Energy Research Scientific Computing Center (NERSC)
- Sponsoring Organization:
- USDOE
- Grant/Contract Number:
- FG02-06ER46304; AC02-05CH11231
- OSTI ID:
- 1523409
- Journal Information:
- Journal of Physics. Condensed Matter, Vol. 29, Issue 42; ISSN 0953-8984
- Publisher:
- IOP PublishingCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
Controlling All‐Optical Helicity‐Dependent Switching in Engineered Rare‐Earth Free Synthetic Ferrimagnets
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journal | October 2019 |
Controlling All-Optical Helicity-Dependent Switching in Engineered Rare-Earth Free Synthetic Ferrimagnets.
|
text | January 2019 |
Controlling All-Optical Helicity-Dependent Switching in Engineered Rare-Earth Free Synthetic Ferrimagnets.
|
text | January 2019 |
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