Abstract
We observe pronounced oscillations in the differential reflectivity of a ferromagnetic heterostructure using two-color pump-probe spectroscopy. Although originally thought to be associated with the ferromagnetism, our studies show that the oscillations instead result from changes in the position and frequency-dependent dielectric function due to the generation of coherent acoustic phonons in the ferromagnetic InMnAs layer and their subsequent propagation into the GaSb. Our theory accurately predicts the experimentally measured oscillation period and decay time as a function of probe wavelength.
- Received 10 May 2005
DOI:https://doi.org/10.1103/PhysRevB.72.153311
©2005 American Physical Society