Abstract
Ultrashort pulse laser techniques are applied to study optically induced modulation in exchange biased ferromagnetic/antiferromagnetic (FM/AF) thin bilayer films (NiFe/NiO). Photoexcitation of the FM/AF interface with subpicosecond laser pulses induces large modulation in the unidirectional exchange bias field ( ) on an ultrashort time scale. The “unpinning” of the exchange bias leads to coherent magnetization rotation in the permalloy film which is time resolved by the experiment and corresponds to a large modulation in the magnetization component ( ), on a time scale of 100 psec.
- Received 17 November 1998
DOI:https://doi.org/10.1103/PhysRevLett.82.3705
©1999 American Physical Society