Spontaneous Hall effect induced by collinear antiferromagnetic order at room temperature

Area of Science:

• Condensed Matter Physics
• Materials Science
• Spintronics

Background:

• Magnetic information is typically stored in ferromagnets, utilizing spin states distinguishable by time-reversal symmetry breaking and read out via the Hall effect.
• Conventional antiferromagnets, lacking macroscopic magnetization and possessing specific symmetries, cannot conventionally host such functions.

Purpose of the Study:

• To experimentally observe a spontaneous Hall effect in a collinear antiferromagnet.
• To investigate the potential of antiferromagnets as a medium for electrical reading and writing of spin states at room temperature.

Main Methods:

• Experimental observation of the spontaneous Hall effect.
• Analysis of spin states and their relation to the Hall effect in FeS.
• Theoretical investigation of the underlying physical mechanisms.

Main Results:

• Observation of a spontaneous Hall effect in the collinear antiferromagnet FeS at room temperature.
• Demonstration that opposite spin states (↑↓ and ↓↑) induce opposite signs of the spontaneous Hall effect.
• Attribution of the effect to a fictitious magnetic field from symmetry-broken antiferromagnetic order, not macroscopic magnetization.

Conclusions:

• The study demonstrates a novel mechanism for electrical readout of spin states in antiferromagnets.
• This discovery opens possibilities for using antiferromagnets as information storage media with minimal magnetization.
• The findings pave the way for electrical writing and reading of spin states in conductive systems at room temperature.