Seebeck rectification enabled by intrinsic thermoelectrical coupling in magnetic tunneling junctions

Area of Science:

• Condensed Matter Physics
• Spintronics
• Thermoelectricity

Background:

• Magnetic tunneling junctions (MTJs) are crucial for spintronics.
• Understanding magnetotransport and microwave rectification in MTJs is evolving.
• Thermoelectric effects in magnetic nanostructures are of growing interest.

Purpose of the Study:

• To report and characterize an intrinsic thermoelectric coupling effect in MTJs.
• To explore the implications of this effect on DC and high-frequency responses.
• To establish a theoretical framework explaining the observed phenomena.

Main Methods:

• Linear response theory
• DC and frequency-dependent transport measurements up to GHz frequencies
• Phenomenological modeling based on Onsager reciprocal relations and energy conservation.

Main Results:

• Demonstrated an intrinsic thermoelectric coupling effect in MTJs.
• Observed a nonlinear correction to Ohm's law in the DC response.
• Reported novel Seebeck rectification and second harmonic generation at high frequencies, with magnetic control.

Conclusions:

• The intrinsic thermoelectric coupling effect in MTJs has significant implications for spintronics.
• The findings provide a new foundation for utilizing spin caloritronics in high-frequency devices.
• The study refines the understanding of magnetotransport and microwave rectification in MTJs.