Ensemble-averaged Rabi oscillations in a ferromagnetic CoFeB film

Amir Capua, Charles Rettner, See-Hun Yang, Timothy Phung, Stuart S. P. Parkin
2017 Nature Communications  
Rabi oscillations describe the process whereby electromagnetic radiation interacts coherently with spin states in a non-equilibrium interaction. To date, Rabi oscillations have not been studied in one of the most common spin ensembles in nature: spins in ferromagnets. Here, using a combination of femtosecond laser pulses and microwave excitations, we report the classical analogue of Rabi oscillations in ensemble-averaged spins of a ferromagnet. The microwave stimuli are shown to extend the
more » ... ence-time resulting in resonant spin amplification. The results we present in a dense magnetic system are qualitatively similar to those reported previously in semiconductors which have five orders of magnitude fewer spins and which require resonant optical excitations to spin-polarize the ensemble. Our study is a step towards connecting concepts used in quantum processing with spin-transport effects in ferromagnets. For example, coherent control may become possible without the complications of driving an electromagnetic field but rather by using spin-polarized currents.
doi:10.1038/ncomms16004 pmid:28656960 pmcid:PMC5493749 fatcat:tfc7khitejba5kyuf4lrwgi6fm