Sensing Spin Precession with Free Electrons

Area of Science:

• Physics
• Materials Science
• Spectroscopy

Background:

• Transmission electron microscopy (TEM) is a powerful tool for nanoscale imaging.
• Characterizing spin dynamics in materials at the nanoscale is crucial for developing advanced electronic and magnetic devices.
• Existing methods for probing spin transitions often lack spatial resolution or require specialized equipment.

Purpose of the Study:

• To develop a novel method for localized, in situ detection of microwave (MW)-driven spin transitions.
• To utilize the free-space electron beam of a TEM as a signal receiver for spin spectroscopy.
• To enable nanoscale exploration of spin excitations.

Main Methods:

• Combining spin resonance spectroscopy with TEM.
• Using the TEM's magnetic field for spin state polarization.
• Employing a custom microresonator for continuous wave MW excitation at GHz frequencies.
• Utilizing phase-locked detection synchronized to MW fields to isolate spin precession signals.

Main Results:

• Demonstrated localized in situ detection of MW-driven spin transitions.
• Successfully used the TEM electron beam as a signal receiver.
• Achieved phase-locked detection of spin precession-induced electron beam deflection.
• Showcased the capability to probe spin excitations at the nanoscale.

Conclusions:

• The presented technique offers a new pathway for nanoscale spin excitation studies.
• This method enables direct visualization of spin dynamics within materials.
• It opens possibilities for in situ characterization of spin-related phenomena in advanced materials.