The key parameter of anomalous Hall effect, anomalous Hall angle, represents the ability of a longitudinal current density to drive a transverse anomalous Hall current density. A large anomalous Hall angle plays a critical role in applications such as anomalous Hall magnetic sensing and spintronic magnetic-domain switching. Over the past 70 years, the anomalous Hall angle has remained at a relatively low level of 0.1–3° (0.2%-5%), and the lack of modulation model and experimental scheme has prevented its effective utilization. 

In recent years, the discovery of magnetic topological materials has provided a material platform for studying spin-related topological states and physical properties, while their topology-enhanced electronic transport properties have opened opportunities for modulating the anomalous Hall angle. The magnetic Weyl semimetal Co₃Sn₂S₂ exhibits a large intrinsic anomalous Hall effect, making it an ideal candidate for realizing the modulation of anomalous Hall angle.

In a study published in Nature Electronics, a research team led by LIU Enke from the Institute of Physics of the Chinese Academy of Sciences reported the modulation of the anomalous Hall angle in the magnetic Weyl semimetal Co3Sn2S2, making progress in magnetic topological materials and physics.

The researchers proposed a dual-variable mathematical model for the anomalous Hall angle, expressing the anomalous Hall angle as a function of the product of longitudinal resistivity and anomalous Hall conductivity for the first time. In the metallic region, the anomalous Hall angle increased with the product of these two parameters. 

For systems with a determined intrinsic anomalous Hall conductivity, the anomalous Hall angle exhibited a maximum value as the longitudinal resistivity increased. Considering the characteristics of intrinsic and extrinsic mechanisms of anomalous Hall conductivity, the researchers proposed experimental schemes for modulating the anomalous Hall angle based on magnetic topological materials.

By leveraging intrinsic and extrinsic degrees of freedom such as topological states, slight doping, temperature, and dimensionality, the researchers designed and validated experiments in the Co₃Sn₂S₂ system. They achieved simultaneous significant enhancements in longitudinal resistivity and anomalous Hall conductivity. This resulted in a zero-field giant anomalous Hall angle of 25° (46%), which was an order of magnitude higher than those of conventional magnetic materials. 

In addition, the researchers developed a novel anomalous Hall sensor, achieving a low-frequency magnetic field detectability of 23 nT/Hz^0.5@1Hz and a Hall sensitivity of 7028 μΩ cm/T, which are three times and 10 times higher, respectively, than those of currently known anomalous Hall sensors.

This study provides a feasible scheme for modulating the anomalous Hall angle, opening a new era of giant anomalous Hall angles of magnetic materials, and demonstrating the topology-principle of high-performance magnetic sensing.