Speaker
Description
Nanoscale ultrafast all-optical tuning of magneto-acoustic devices is of significant scientific and technological interest, particularly in areas of energy efficient data storage and information processing. Ultrafast generation and control of high frequency nanoscale surface acoustic waves (SAWs) in the first order magneto structural phase transitions can be used to precisely control such devices. Utilizing recently developed time-domain Extreme ultraviolet diffuse scattering spectroscopy, we demonstrate the generation and detection of broadband nanoscale surface phonons featuring high frequencies and large wavevectors, exhibiting anisotropic propagation in biaxially anisotropic epitaxial BCC FeRh thin films. We probe the surface phonons in layered stack of Pt(3 nm)/FeRh (40 nm) /3C-SiC (100 nm)/Si (381 $\mu$m) within the in-plane wavevector range of 0.028 nm$^{-1}$- 0.1 nm$^{-1}$ and frequency range of upto 50 GHz corresponding to phonon wavelengths of 62 nm -224 nm. We observe the square-shaped contours in time-domain scattering and frequency-domain iso-frequency curves corresponding to bi-axial anisotropy in cubic epitaxial FeRh which agree with corresponding theoretical simulations.
| Scientific Topics | Solid State Physics |
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