Nanoscale Antiferromagnetic Domain Imaging using Full-Field Resonant X-ray Magnetic Diffraction Microscopy

Area of Science:

• Condensed Matter Physics
• Materials Science
• Magnetism

Background:

• Physical properties of magnetic materials depend on microscopic and mesoscopic structures.
• Experimental access to mesoscopic structures, especially in antiferromagnets, is challenging due to zero net magnetization.

Purpose of the Study:

• To visualize antiferromagnetic (AF) domains in the spin-orbit Mott insulator Sr2IrO4 at mesoscopic length scales.
• To investigate the impact of mesoscopic domain structures on the material's physical properties and symmetry.

Main Methods:

• Combined full-field microscopy and resonant magnetic X-ray diffraction.
• Visualized AF domains in Sr2IrO4 over an area of ≈0.1 mm² with ≈150 nm spatial resolution.

Main Results:

• Revealed an intertwining of two AF domains on a length scale comparable to the domain wall width (545 nm).
• Demonstrated that these mesoscopic structures significantly influence the sample surface and can lead to unexpected macroscopic responses.
• Showed that inversion symmetry becomes ill-defined at the mesoscopic scale, despite being preserved at the microscopic level.

Conclusions:

• The novel technique provides unprecedented insight into AF domain structures.
• Understanding mesoscopic structures is critical for a comprehensive grasp of antiferromagnet properties.
• This work highlights the importance of mesoscopic phenomena in determining macroscopic physical behavior.