Anomalous Nernst Effect-Based Near-Field Imaging of Magnetic Nanostructures

Area of Science:

• Condensed Matter Physics
• Materials Science
• Nanotechnology

Background:

• The anomalous Nernst effect (ANE) produces an electrical signal perpendicular to magnetization and temperature gradients in magnetic metals.
• Nanoscale temperature gradients are achievable using laser-excited atomic force microscope tips for high-resolution imaging.
• Previous studies mapped in-plane magnetic textures, but the role of out-of-plane temperature gradients remained unexamined.

Purpose of the Study:

• To investigate the spatial distribution of temperature gradients in ANE measurements.
• To demonstrate the reliability of ANE for nanoscale imaging of magnetic domains.
• To extend ANE imaging capabilities to study out-of-plane magnetization and thermoelectric properties.

Main Methods:

• Utilized laser-induced nanoscale temperature gradients with an atomic force microscope tip.
• Employed a magnetic vortex core as a model system to validate ANE imaging.
• Integrated finite element modeling to analyze temperature distributions and ANE signals.
• Applied ANE imaging to racetrack nanowires to detect out-of-plane magnetization.

Main Results:

• Confirmed ANE's capability for nanoscale imaging of magnetic domains with ≈70 nm resolution.
• Revealed significant in-plane temperature gradients alongside out-of-plane gradients.
• Successfully extended ANE imaging to analyze out-of-plane magnetization in nanowires.
• Demonstrated the inverse problem's utility for deducing nanoscale temperature distributions.

Conclusions:

• ANE-based thermoelectric imaging offers a powerful tool for nanoscale magnetic characterization.
• The technique provides high spatial resolution for studying complex magnetic textures and device structures.
• These findings are crucial for advancing thermoelectric imaging in antiferromagnetic spintronic devices.