Magnetic field

Physics

Hall effect

Electron

Magnetometer

Spin Hall effect

Materials science

Quantum Hall effect

Spin polarization

Condensed matter physics

Magnetization

Thermal Hall effect

Quantum mechanics

Ferromagnetism

Nature Electronics

The anomalous Hall effect is a time-reversal symmetry-breaking magneto-electronic phenomenon originally discovered in ferromagnets. Recently, ruthenium dioxide (RuO2) with a compensated antiparallel magnetic order has been predicted to generate an anomalous Hall effect of comparable strength to ferromagnets. The phenomenon arises from an altermagnetic phase of RuO2 with a characteristic alternating spin polarization in both real-space crystal structure and momentum-space band structure. Here we report an anomalous Hall effect in RuO2 with an anomalous Hall conductivity exceeding 1,000 Ω−1 cm−1. We combine the vector magnetometry and magneto-transport measurements of epitaxial RuO2 films of different crystallographic orientations. We show that the anomalous Hall effect dominates over an ordinary Hall contribution, and a contribution due to a weak field-induced magnetization. Our results could lead to the exploration of topological Berry phases and dissipationless quantum transport in crystals of abundant elements and with a compensated antiparallel magnetic order. By combining vector magnetometry and magneto-transport measurements of epitaxial films with different crystallographic orientations, an anomalous Hall effect can be measured in collinear altermagnetic ruthenium dioxide with an anomalous Hall conductivity exceeding 1,000 Ω–1 cm–1.

An anomalous Hall effect in altermagnetic ruthenium dioxide