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Spin oscillations in antiferromagnetic NiO triggered by circularly polarized light
Takuya Satoh1, Sung-Jin Cho, Ryugo Iida
1Institute of Industrial Science, University of Tokyo, Tokyo 153-8505, Japan.
Physical Review Letters
|September 28, 2010
Summary
Circularly polarized light nonthermally induced coherent spin oscillations in nickel oxide (NiO) via an effective magnetic field. This novel mechanism drives spin dynamics even in antiferromagnets lacking net magnetic moments.
Area of Science:
- Solid State Physics
- Magnetism
- Optics
Background:
- Antiferromagnetic materials exhibit unique spin dynamics.
- Controlling spin oscillations is crucial for spintronics.
- Non-thermal induction of spin dynamics offers new possibilities.
Purpose of the Study:
- To investigate the non-thermal induction of coherent spin oscillations in nickel oxide (NiO).
- To explore the role of the inverse Faraday effect in driving antiferromagnetic spin dynamics.
- To characterize the frequencies of induced spin oscillations.
Main Methods:
- Utilizing circularly polarized laser pulses to excite NiO.
- Applying the inverse Faraday effect to generate an effective magnetic field.
- Measuring antiferromagnetic spin oscillation frequencies using THz spectroscopy.
Main Results:
- Coherent spin oscillations were successfully induced in NiO non-thermally.
- The inverse Faraday effect was identified as the driving mechanism.
- Measured frequencies of 1.07 THz (out-of-plane) and 140 GHz (in-plane) were observed.
Conclusions:
- Circularly polarized light can non-thermally induce spin oscillations in antiferromagnets.
- The time derivative of the effective magnetic field drives spin dynamics, even in compensated antiferromagnets.
- This mechanism provides a novel route for controlling antiferromagnetic spin oscillations.
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