Metamagnetic multiband Hall effect in Ising antiferromagnet ErGa₂

Area of Science:

• Condensed Matter Physics
• Materials Science
• Magnetism

Background:

• Frustrated rare-earth intermetallics are key for emergent magnetotransport properties via exchange coupling.
• Metamagnetism, a first-order magnetic phase transition, is linked to nontrivial spin structures and topological Hall effects (THE).

Purpose of the Study:

• Investigate metamagnetism-induced Hall anomalies in single-crystalline ErGa2.
• Clarify the origin of these anomalies, distinguishing them from anomalous Hall effect and THE.
• Explore the role of 4f-5d interactions in observed Hall responses.

Main Methods:

• Synthesis of single-crystalline ErGa2.
• Magnetotransport measurements under external magnetic fields.
• Analysis of Hall anomalies and their correlation with magnetization processes.

Main Results:

• Observed Hall anomalies in ErGa2 that resemble THE but without noncoplanar spin structures.
• Ruled out anomalous Hall effect and THE as the primary cause.
• Attributed anomalies to 4f-5d interactions inducing band-dependent mobility modulation.
• Demonstrated a pronounced multiband Hall response during magnetization.

Conclusions:

• The observed Hall anomalies are a 'metamagnetic multiband Hall effect' driven by mobility modulation, not topological phenomena.
• Findings are relevant for understanding Hall signals in itinerant metamagnetic systems, irrespective of spin structure.
• Emphasizes the importance of accurately identifying Hall signals to avoid misattributing them to emergent magnetic fields.