Greatly enhanced magneto-optic detection of single nanomagnets using focused magnetoelastic excitation

Magnetization dynamics of nanomagnets directly determine the performance of magnetic storage and memory devices. Here, we report a 10-times enhancement of magnetization dynamics excitation of single nanomagnets using focused surface acoustic waves (SAWs), compared to conventional optical excitation....

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Bibliographic Details
Published in:Applied physics letters 2020-05, Vol.116 (21)
Main Authors: Yang, Wei-Gang, Schmidt, Holger
Format: Article
Language:English
Subjects:
Applied physics
Data storage
Dynamics
Excitation
Magnetic storage
Magnetism
Magnetization
Memory devices
Oscillators
Surface acoustic waves
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Summary:Magnetization dynamics of nanomagnets directly determine the performance of magnetic storage and memory devices. Here, we report a 10-times enhancement of magnetization dynamics excitation of single nanomagnets using focused surface acoustic waves (SAWs), compared to conventional optical excitation. SAWs are generated via ultrafast optical excitation of an arc-shaped phononic grating and focused onto a single nanomagnet located at the focal spot of the grating. Thanks to the robust resonance excitation, we observe the strain-controlled ultrafast magnetization dynamics in a sub-100 nm single nanomagnet. This improved excitation efficiency was applied to exciting SAWs in four sets of gratings with different pitches using a single laser spot. This enabled selective excitation of any one of four identical nanomagnets at different frequencies simply by tuning an external magnetic field. This all-optical technique provides a method of addressing individual magnetic nano-oscillators and studying their intrinsic magnetization dynamics.
ISSN:0003-6951
1077-3118
DOI:10.1063/5.0006461